Guide to Energy-Efficient Systems for Luxury Residential Projects
Everything to Consider When Beginning a New Build
If you’re working on an energy-efficient luxury home, then you already know that there are three main elements that matter most; the ability to reduce operational and energy costs, ease of maintenance, and effective operations throughout the system’s life.
The construction industry is highly dynamic, and the requirements, expectations, and baselines for minimum energy conservation are constantly changing. This is why architects, general contractors, engineers, and design teams are often challenged to meet and exceed these efficiency expectations. In this guide, we’ll highlight everything you need to know about energy-efficient mechanical systems for luxurious residential homes, including the most relevant considerations.
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— Owner’s Project Requirements
— Swimming Pool and Spa Designs
How Does One Design and Install a Highly Efficient Mechanical System
While Meeting a Client’s Expectations?
Understand the Client’s Expectations: Client Intake Form
Understanding our clients is crucial as it helps us complete projects based on industry standards and still meet their expectations. The industry may have set specific parameters, but they don’t always coincide with the client’s needs. For instance, the code states that the heating setpoint should be 70°F and the cooling setpoint 78°F. But what if the client wants cooling at 70°F?
At the beginning of every engagement, we provide the client with a checklist to fill out and express what is important to them. Our client intake form also educates the client on these items and helps them determine their expectations at the end of the build. Once we have gathered all the information, we then store it and use it for the project’s entirety. This is extremely important because most projects have a long time frame, and the period between the start of design to the day the client moves into their home can be several years. If the client’s expectations are undocumented, then we can miss critical information.
Owner’s Project Requirements
We take critical details from the client intake form and then generate an Owner’s Project Requirements (OPR) form to document client expectations. This form is presented to the client during an in-person meeting, where we interact with them and ensure that we truly understand their requirements. The best part is that an OPR is a living document, so we can update it as required. This ultimately ensures that all their energy-efficient mechanical system expectations are fully met when the client moves into their residence.
Admit it; this is one of the most exciting times for professionals in building science and mechanical engineering; there are multiple alternatives to designing stellar projects. So, how do we decide the best technologies and schemes for a project? We use a trade-off analysis! A trade-off analysis outlines the building envelope and mechanical systems that can meet the project requirements. It is presented to the client, design, and construction team, and its main aim is to educate them on the best systems that can heat and cool all aspects of the residence through financial paybacks and weighting parameters.
The best practice when it comes to trade-off analysis is to first design the best building envelope to reduce the mechanical system size. This subsequently reduces the residence’s operating costs. With a good building envelope, we are also able to install mechanical systems that once seemed prohibitively expensive. Keep in mind that insulation is cheaper than mechanical systems and offers the biggest bang for the buck. However, because a luxury residential project is unique, each insulation and window scheme needs to be evaluated based on the one that will have the biggest impact.
To evaluate the best insulation, windows, and mechanical systems, we use a model that generates each scheme’s energy consumption and corresponding energy costs. This model is more effective than the standard Manual J as required by code, but we ultimately use the Manual J for code compliance. Once we’re armed with this cost data, we can perform a payback analysis of each of the schemes.
We also consider certain elements that relate to the occupant’s comfort, architectural aspects, and other parameters. For example, there is no payback on radiant floor heating, but it significantly enhances occupant comfort. We perform a weighting scheme to present to the client to account for these intrinsic values. Using this tool, we are able to educate them using dollars and base values that they easily understand, allowing them to make a decision on what fits their values and goals for the project.
This kind of upfront work ultimately allows us to develop the proper insulation scheme, windows, and mechanical systems that meet the client’s expectations.
The same way a building is supposed to keep water out, it is just as important for it to keep energy in. Building science has taken huge leaps in the last 20 years, and with better methods and analytical tools emerging, it’s expected that there will be more developments in the coming years.
One of the key elements of resilient luxurious residential homes is the building envelope and, the Passive House standards are not only enhancing industry growth but also providing standards that can be turned into actionable details and processes. For instance, we now have materials that control water vapor and air pathways, allowing us to push the tightness of our buildings. A tighter envelope then creates a comfortable space and reduces energy consumption, ultimately ensuring that drafty homes are a thing of the past.
Today’s high-quality design is more than simply specifying the insulation. The insulation materials are as important as where they are applied, which is why the thermal envelope needs to be clearly defined, detailed, and fully specified. This is because a complicated construction can lead to condensation and poor performing assemblies. In addition to the poor energy efficiency, condensation can also lead to mold growth and eventually deterioration of the building.
When it comes to luxury residential projects, the architecture should always go above & beyond code minimums for insulation schemes to consider the functionality of the building envelope. This is important during the design process and helps in creating a final design that is fully detailed for a buildable design. Typically the design team will need to consider the final trim level due to higher performing windows, exterior wall insulation that eliminates thermal breaks, and a taller truss or rafter heel. Most of the time, detailing how the steel acts as a thermal bridge in luxurious residences is often overlooked, and this ends up creating substantial energy losses.
If the residence has wine rooms, indoor pools, spas, and saunas, then it will require special consideration. This is because when the installation is done improperly, it leads to premature failure of the room, and in some cases, failure of the entire building. However, the proper selection of materials and construction ensures that the moisture transport is controlled from these high humidity areas to lower humidity areas.
When the assemblies become complex, and there is the use of non-standard materials, multiple building layers, or deviations from the accepted industry standards, advanced modeling of the assembly is required. This advanced modeling, called finite element analysis (FEA), calculates the temperature throughout an assembly when subjected to varying outside air temperatures. It allows us to then calculate the saturation pressure at these locations and determine the acceptable relative humidity and associated dew point through the assembly. This analysis ultimately ensures that even under the most extreme design conditions, the assembly will still perform as expected.
We noticed that one consideration that is often overlooked when making the building envelope a high-performing assembly is that exterior noises will be diminished, and interior noises will become more prevalent. This is why we recommend that the design team identify the best way to isolate areas that generate noise because mechanical systems are often loud, and the type of system and where it is located highly impact whether our ability to meet the client’s expectations.
Indoor Air Quality
Homes breathe the same way we do. So, the air that friends and family exhale should be withdrawn from the building and replaced with fresh, filtered, conditioned air from outside. This is because the quality of the air we breathe is directly related to our health & wellbeing, and an inappropriate turnover rate can result in drowsiness, headaches, and compromised immune systems. Currently, using a simple fan and some fresh air ducting to a furnace is inadequate, which is why we use Heat or Energy Recovery Ventilators to control the precise amount of filtered & tempered fresh air that gets into the residence. This ultimately ensures the residence has energy-efficient and high-level indoor air quality (IAQ).
Through the OPR, we gain information such as whether the residence’s occupants have allergies or sensitivity to other airborne compounds to design the proper filtration. This is the only method that has been proven 100% effective in providing the highest indoor air quality. So, by selecting the proper filtration scheme, we are able to supply the home with high-quality air that’s on the level of hospital operating rooms.
We integrate technology into monitoring IAQ by using distributed sensors that constantly sample the health of your living environment while advanced data analytics interpret the results and adjust the zone turnover rates accordingly. This then provides a healthy living environment round the clock, while the adjustable concentration setpoints ensure the air inside the home meets the latest standards, and most importantly, the client’s expectations. The technology also helps combat carbon dioxide, and VOC buildup provides a ventilation performance metric for all sensors in the home and then lets the occupants know whether the IAQ is at the levels they require, much like the reading of a thermostat.
Ground Source Heat Pump (Geothermal)
Geothermal heat pumps (GHP) are designed to harness energy from beneath the earth’s surface and use it to heat and cool buildings. They’re also referred to as earth energy systems, ground source heat pumps, and geo-exchange. These names are region-specific and might change depending on where you live, which is why most industry experts prefer to call them geothermal systems. Geothermal heat pumps use technology that leverages the near-constant temperature below the earth (regardless of the season) to maintain optimal temperatures.
Although many parts of the country suffer seasonal temperature extremes, ranging from blistering heat in the summer to sub-zero freezing in the winter, the ground temperature generally remains consistent and ranges from 45°F (7°C) to 75°F (21°C) depending on latitude. This ground temperature, like that of a cave, is warmer in the winter than the air above it and cooler in the summer. During winter, the heat pump system removes heat from the exchanger and supplies it into the indoor spaces to warm them or to heat water. However, the process is reversed during summer, with the heat pump transferring heat from the inside air to the heat exchanger.
GHPs are four to six times more efficient than the finest air-source air conditioners and about 50% more efficient than the top-rated gas furnaces; their emission levels are lowest in comparison with any HVAC applications. The Coefficient of Performance (COP) of most geothermal heat pump systems is between 3-4.5, which means that for every unit of energy the occupants use to power the system, 3-4.5 units of heat are provided. GHS systems also have the lowest emissions, reduce carbon emissions from a building’s energy use by up to 50%, and release practically no emissions on-site. Ultimately, the increased usage of GHPs would significantly cut global emissions for a healthier, cleaner planet.
The financial benefits of GHPs don’t stop there. Many incentives are available to buildings that use geothermal systems, including federal tax credits and energy rebates. For instance, the federal tax credit for commercial applications has no cap and is equal to 10% of the entire system cost, with a five-year Modified Accelerated Cost Recovery (MACR) system depreciation option or 100% first-year depreciation on a whole system and cost basis. Building owners can also apply for these incentives because customers who install energy efficiency initiatives are eligible.
Air Source Heat Pump
Air source heat pumps are a cost-effective, energy-efficient, and ecologically responsible solution for heating and cooling your home all year. These pumps are powered by electricity, but they are inexpensive to run because of their high efficiency, making them an energy-efficient alternative to furnaces and air conditioners. Most air source Heat pumps, like your refrigerator, transfer heat from cold to warm spaces using electricity to make cool spaces cooler and warm areas warmer. Even in temperatures as low as 30°F, Air-source pumps are remarkably effective at drawing heat from the outside air. In winter, they capture and condense heat from the outside air and bring it indoors. However, in summer, they work just like an air conditioner, absorbing heat from inside the home and ejecting it outdoors.
During cold weather, air-source heat pumps may heat a home with efficiencies of over 400 percent. Conventional heating systems, especially those that run on gas, oil, or propane, on the other hand, have efficiency ranging from 80 to 97 percent. This is because some heat, moisture, and other combustion byproducts always go up the chimney when fossil fuels are used for heating, making it impossible to achieve 100% efficiency. As a result, most homeowners end up paying for a lot more “heating potential” than they actually get.
However, the usable heat produced is substantially greater than the energy purchased at the meter when the heat pump efficiency is assessed. For instance, the complete winter’s efficiency is normally in the 200-250 percent range in cold climates. This means that homeowners get between two and three times the amount of heat for the home than they pay for at the meter throughout the winter. In addition, cooling efficiencies are also significantly high, and heat pumps with variable speed capacity for cold climates cool at two times the efficiency of standard window air conditioners.
Because of their high efficiency, heat pumps are the cleanest alternative available for people that prioritize lowering their carbon footprint. Unlike burning oil or gas, which will always emit carbon dioxide and energy from the grid, air source heat pumps tend to become greener each passing year. It’s no surprise that their average carbon emissions (for the northern United States) are substantially lower than any other fuel. Additionally, in most regions, the electric utility providers offer “green” energy solutions that are partially or entirely generated by renewable energy or other green technology.
Net Zero (Solar Photovoltaic, Solar Thermal, and Offsets)
A Net Zero Energy Building is a type of design and construction that tries to create an electricity-efficient, grid-connected building that can generate enough energy from renewable sources to meet its own demand. As a result, these structures have a near-zero energy consumption, which means that the total energy required by the building on a yearly basis is roughly equal to the amount of renewable energy generated on-site or nearby.
A statistical estimate shows that buildings account for about 40% of all US energy consumption and a similar proportion of greenhouse gas emissions. Net Zero buildings emit fewer greenhouse gasses into the atmosphere than other comparable non-ZNE structures. And even though they do consume nonrenewable energy and emit greenhouse gasses at times, they also reduce energy consumption and emissions elsewhere by the same amount.
You should note that almost all Net Zero Energy Buildings have a connection to the electric grid. This is important as it allows for the residents to use electricity from traditional energy sources when the renewable energy that they’re generating is unable to meet the energy load of the building. However, when the energy generated on-site is more than the energy requirements of the building, the excess energy produced is supposed to be redirected to the utility grid, if applicable. This will then be used later to offset days when there’s excess energy demand, ultimately resulting in net-zero energy consumption. You should, however, note that the differences in how jurisdictions calculate the payment for the energy and utilities exported into the grid have a significant impact on the project economics. So, we carefully evaluate them.
Irrespective of the measure used to define a Net Zero Energy Building, reducing energy consumption by creating an efficient building design is one of our core objectives and the highest focus of all Net-zero energy projects. This is because focusing on energy efficiency is usually the most cost-effective method that guarantees the highest ROI. So, optimizing the efficiency opportunities prior to establishing renewable energy plans also reduces the overall cost of the project. The good news is that design teams can make the most of technologies and designs by using modern energy analysis techniques.
Some of the energy-saving design methods and features that we consider include high-performance envelopes, daylighting, careful selection of windows and glazing, air barrier systems, sun control and shading devices, passive solar heating, water conservation, and natural ventilation. We also use efficient systems and equipment once the building loads have been decreased using electric lighting controls, energy-efficient lighting, geothermal heat pumps, and high-performance HVAC. You should, however, note that microturbines, fuel cells, and combined heat & power systems, are examples of energy conversion technologies that do not create renewable energy. They instead transform traditional fossil fuel energy into electricity and heat, which can be classified as energy efficiency measures.
After efficiency measures have been effectively adopted, renewable energy technologies can be used to meet the remaining energy requirements.
One PV device is known as a photovoltaic cell, and it’s used to convert sunlight into electrical energy. Most of the time, individual photovoltaic cells are generally small and typically produce around 1 or 2 watts of solar power. This is why they’re often connected in arrays to form larger units known as solar panels to boost their solar power output.
Solar panels can either be used individually, or you can connect several solar panels to create arrays. They are then connected to the electrical grid as part of a solar-powered system, and because of this modular structure, solar-powered systems can be built to meet almost any electric power needs.
Solar Thermal Systems
A solar thermal system converts energy from the sun into heat, which is subsequently transported to the spaces in the building. It has been demonstrated to be effective, dependable, and low maintenance.
Solar thermal panels work in tandem with an immersion heater, collector, or boiler. The collector keeps the water from freezing in the winter by using the sun’s rays to warm up a transfer fluid (usually a mixture of glycol and water). This heated water is delivered to a heat exchanger that’s located in a water cylinder, and the water inside is warmed by the heat from the exchanger. The water then returns to the collectors for reheating after the liquid has released its heat.
When there is enough heat available, a controller ensures that the fluid circulates to the collector.
Swimming Pool and Spa Design
Pool and Spas have become integral to the enjoyment of luxury residential projects. This, combined with the outdoor kitchens and sliding doors, brings the indoor/outdoor living experience to the residence.
The only way a resident can enjoy a pool or spa is when they can easily achieve comfortable water temperatures during the desired season or time of the day. This is where the Client Intake Form and the OPR comes into play. It defines the preferred operating temperatures and seasons of the pool and spa. These parameters are often changing, and we have noticed that what was considered normal operating temperatures in the past is rarely being accepted by modern clients.
To meet client expectations, it is vital to provide the proper design that meets their requirements, local building codes and gives the homeowner the chance to save money by ensuring the pool and spa operations are energy efficient. For instance, improperly designed water heating systems may cause high fuel, gas, or electricity usage without meeting the desired water temperatures. If you also include a feature that’s prohibitively expensive to operate, it will result in it not being used and ultimately abandoned. Even worse, undesired high temperatures may occur during pool or spa operations, jeopardizing the health of the occupants.
The best way of reducing the energy consumption of the pool and spa is by using state-of-the-art technologies. These technologies often combine the home’s cooling system with the pool heating system allowing for overall efficiency. To implement such a solution, the designer needs to use simulation and calculations to accurately analyze the ideal size. They should also compare the performance of the heating equipment during its operation and through its lifecycle. This will ultimately help them reduce the lifecycle costs, reach acceptable payback periods, and reduce CO2 emissions without compromising the occupants’ comfort. You should, however, note that to achieve this kind of efficiency, the design team needs to collaborate with the construction team.
Radiant Heating and Cooling
If you’re looking for the best way to achieve the ultimate occupant comfort, then you should consider radiant heating and cooling technology. Radiant heating is similar to the concept of standing by a campfire. When you’re facing the fire, it warms the front part of your body because of the heat being radiated to your body. The backside of your body, on the other hand, is, however, cold because it is radiating energy to the cold night air. This ultimately causes you to rotate your body to stay warm. This is the same way a radiant heating and cooling system works. The best part is that radiant heating only warms the surfaces and not the air. This is good because the surfaces are more stable, and radiant heating causes minimal temperature fluctuations. One of the most popular heating technologies is radiant floor heating. This is because, in addition to warming the surfaces, hot air rises because it becomes more buoyant as it is heated. Most of the time, a lower thermostat setting achieves the desired occupant comfort, which results in energy savings. There are, however, different methods of installing a system to gain the best energy efficiency. But, the installation that has the lowest supply water temperature typically achieves the lowest energy consumption.
Creating chilled water is relatively easy, especially when residents already use a heat pump. This is due to the fact that they already have the radiant infrastructure in place on the floor, so it’s easy to make changes to the overall design. For starters, the same way radiant heating heats the surfaces, radiant cooling cools them. However, it’s not just a trivial scheme, and you need to get it right. It requires a good design and a sophisticated control scheme and system. We are able to make a radiant floor cooling system that’s as granular as a heating system. However, depending on the loads, we may need to use some form of cooling to meet the entire cooling load. We can either supplement this with a partial radiant ceiling or a forced-air system; both schemes significantly increase the effectiveness of the radiant floor cooling.
With modern technologies, it’s essential to adapt the Radiant ceiling into the design. This is because the ceiling is responsible for cooling the air that falls, making it a critical aspect of the cooling process. It’s also highly crucial in the heating process because it offers a larger heated surface compared to the floor, which significantly helps overcome the lack of air heating.
Since it’s a relatively new concept, radiant cooling has not been fully adopted yet by the luxury residential market. This technology is, however, ideal for your leading-edge clients.
Snow accumulation on driveways, walkways, exterior steps, or patios and traditional snow removal methods such as salting or plowing could lead to undesired effects on the constructions and even create hazards to the users of these spaces. For instance, pavement damage may occur due to frost action or plowing, especially when surfaces are covered with pavers. Salting, on the other hand, may damage the landscape, pavement, and surrounding environment when it is swept or tracked into buildings.
Modern snowmelt systems provide automated snow and ice removal using thermal energy, which eliminates the use and effects of mechanical or chemical means. As the snow is melted, it doesn’t create banks or piles of removed snow; thus, the property can achieve a better appearance and safe surfaces that guarantee the reduced risk of slips, falls, or vehicular accidents.
Snowmelt systems consist of nonmetallic tubing embedded into the concrete of exterior surfaces like driveways, walkways, or patios. They use a heated antifreeze solution that circulates through the pipes, heating the surfaces while either melting the formed ice or snow or preventing its formation. The programmed controller of the system is commanded by temperature and humidity sensors, which offer the heat source and the continuous fluid circulation until surfaces are free of snow or ice.
DMA provides high-efficiency automated snowmelt systems design. Supported by software tools, we provide energy calculations, tubing layouts, equipment selections, and detailed sequences of operations that ensure the system will operate under proper conditions and avoid the waste of energy.
Controls Above the Audio-Visual Systems
Most modern homes use automation systems such as SAVANT or CRESTRON to control lighting, audio, and visual aspects. Typically, the architecture ensures that the residents don’t need thermostats on the walls, especially in large homes with multiple zones, and use a temperature and humidity sensor. This is why the home automation systems have a built-in thermostat function that acts as the interface with the heating, cooling, and ventilation systems, ultimately offering a seamless client experience within the residence.
The key to high-performing heating, cooling, and ventilation systems relies on a building automation system, BAS, which is typically misunderstood. These robust systems are independent, but they can integrate with the home automation system, energy monitoring, weather stations, irrigation. In addition, they use the integration to act as a data warehouse that can be used to generate dashboards and other interfaces for the client outside of the Home Automation System.
Additionally, modern heating and cooling systems often have to serve multiple areas at once, and their efficiency determines their ability to meet the client’s expectations. The BAS system allows for advanced control sequences that enable it to meet the required demands. However, just serving a demand is not adequate, so it must be done effectively and efficiently.
The luxury residential market is constantly faced with increasing expectations when it comes to noise, energy, and the ultimate in occupant comfort. So, using systems that modulate to precisely meet the demand is critical. BAS systems allow engineers and technicians to monitor a system remotely and even make changes to a system when not on site. The systems can also self-diagnose, send emails to technicians when a component is operating out its specific operating range, or even fail.
We can implement advanced sequences given the ultimate occupant comfort by indoor air quality monitoring systems and weather systems. We can also further optimize a system’s operation by taking advantage of advanced algorithms, machine learning. All this results in a residence that has a lower operating throughout its lifecycle.
Commissioning is a quality-focused process designed to enhance the delivery of a project. The goal is to provide the client with peace of mind knowing that their home is performing as it was designed to perform. This version of quality control can increase the efficiency of the building, optimize occupancy comfort, and even prolong the lifespan of the systems. Commissioning can be integrated into the construction of new buildings or can be applied to existing homes as a sort of “tune-up .”This retro-commissioning can increase occupancy comfort and save homeowners a surprising sum of money by reducing utility consumption.
For a new structure, this process begins even before the ground is broken. The commissioning team first reviews the equipment wish list to ensure all the homeowners’ deliverables will be met. Then, as the building is erected, the Commissioning Engineer continues their quality control work such as inspections of the ductwork and radiant tubing, damper and diffuser locations, mechanical equipment make and model, and alignment with manufacturer’s installation manuals. This is done to verify that the homeowner will be getting the very best performance out of their equipment. These periodic inspections take place from the initial framing to the last bit of trim work. The commissioning team also ensures that adjustments are materialized in the home as plans are amended and fine-tuned. Additionally, periodic meetings and reports are administered to the architect, general contractor, and mechanical contractor to keep everyone on the same page throughout the construction and prevent any identified deficiencies from slipping through the cracks and going unaddressed.
Most people don’t realize that commissioning services continue even after the occupants have moved in. The thing is that the way a home is laid out and the way it’s inhabited is as unique as a fingerprint. Even with the innovative design and modeling software available today, it is difficult to pre-determine exactly how a home reacts to being lived in. For instance, air quality, flow paths, and zone temperatures are highly dependent on occupancy habits and furniture arrangement.
Commissioning services fine-tune the systems responsible for keeping the occupants healthy and comfortable in real-time. It enables the functionality, efficiency, and the correct sequence of operations to be verified by measuring setpoints, consumptions, and frequencies throughout the building and HVAC equipment across all four seasons. These services also decrease zone temperature variance and allow the equipment to work with ease and less frequently to maintain setpoints. As a result, the home uses less energy, and the equipment lasts longer. Think of it as a powerful strategy to make a building work for the occupants.
Retro-Commissioning is a non-invasive strategy to increase a home’s energy efficiency and improve comfort. This is done by simple, functional tests for the equipment, reviewing the home’s sequence of operations, visual inspections, and collecting data from the sensors distributed throughout the building. This data provides a quantitative map of how effective the equipment is at maintaining the setpoints of each zone in the home, making it easy to make adjustments throughout the HVAC infrastructure to optimize its performance. This results in an efficient and accurate thermostat.
Let Us Help You Actualize Your Project
Are you looking for a partner to work with on your upcoming luxury residential project? We’d love to help! At DMA, we are passionate about making buildings with low operating costs, high comfort levels, and great efficiency. So, don’t hesitate to reach out to us for all your construction needs.