Building Strategies: Using Energy Modeling to Measure Home Performance

When designing a new home, what qualifies as important to you? How about lots of natural light, well regulated heating & cooling for comfort? What if you had all of that plus reduced utility bills? When you're designing a home, wouldn't it be great if there was a way to evaluate how much it would cost to live in it after it was built? If you said yes, then you're on the right track. Here at Mottram Architecture we use energy modeling on all of our homes. This helps us to evaluate what the best options are for our clients budget now, and for the life of the home.With the exception of the solar panels you will see on a net zero home, at first glance you might not realize it is anything other than another beautiful home. What makes this type of home so special is often the unseen features. If you are planning to build a home anyway, why not make some early decisions that can make your home smarter, cheaper to live in and more comfortable. With energy modeling, we can evaluate trade off's. What we mean by trade off, for example, would be more insulation for less heating system. The savings for adding more insulation will not eliminate a heating system, but it can make the heating system smaller. So even though the insulation cost more to install, a smaller heating system will cost less, and as costs rise with the economy, a smaller heating system will cost less to operate. For this reason, a great building envelop with the right type and amount of insulation, typically pays for itself in no time.A common misconception is the average consumer cannot afford to build to the standards of net zero, however this is a feasible goal for anyone ready to build!  It’s possible to keep costs comparable to conventional construction simply by planning ahead, and that’s what we do best here at Mottram Architecture.5 Reason Why Using Energy Modeling to Evaluate Home Performance is So Important:

1. Using an energy model can help to evaluate the cost difference in using double pane vs triple pane windows. Although using triple pane windows has other advantages with thermal comfort and moisture mitigation, sometimes the increased costs associated with high performance windows can keep you from proceeding towards net zero.
2. Energy modeling also allows evaluation of different wall systems. We always strive to get R-40 minimum in the walls and R-60 in the ceiling. However, there are a number of ways to get to that level of insulation. Different contractors and different sites make certain materials easier to work with or cheaper to install. Without reducing the overall effectiveness of the building envelop, energy modeling can take into account how everything works as a whole.
3. When building an efficient home, there are several programs that you can take advantage one. One of the most valuable programs for a homeowner can be the Energy Efficient Mortgage. This allows a homebuyer to extend the amount of money they can borrow by offsetting the extra money in the mortgage payments with lower monthly bills. Using an energy modeling software allows Mottram Architecture to evaluate the cost of better building practices against the monthly savings to the homeowner.
4. When building a net zero home, it's important to evaluate how you get to zero energy. There are a number of programs you can participate in, but energy modeling is the key to having a great design that will perform well once constructed. Energy modeling takes into account how the building uses energy and how much energy the building needs to produce to hit the zero energy target.
5. Here at Mottram Architecture we believe in integrated design. That's one of the reasons we do an energy model on each home we design. We've learned a lot about high performance building over the years. Everything from indoor air quality to building construction techniques. The reason why energy modeling is so important to us, is it shows us where there is a weakness in our design. Are there too many windows on the wrong side of the house. Is there enough shading to prevent overheating. It may sound silly in a heating climate, but in the summer time it's just as important to stay cool inside your home. But maybe most importantly, what is it going to cost to operate this home and how can we make it better.

These are just a few reasons why we do energy modeling at Mottram Architecture. If you're thinking about building a home, it's always a wise idea to know what it's going to cost you to live in it after it is built. Let us help you make the right design decisions, so you not only love your new home, but so your comfortable living there for many years.  

Do Homebuyers Want "Energy Upgrade" Packages?

We were recently featured in the Insulation Institute's Quarterly Newsletter. Below is the story by Stacy Fitzgerald-Redd. For more information on the Insulation Institute, click HEREAre builders missing the mark by not offering upgrade options for HERS-Scored homes?Homebuyers like choices. Builders, ever eager to meet the desires of their buyers, typically offer a dizzying array of choices in products, finishes and designs to suit a wide variety of styles.  Yet seemingly few builders offer consumers a choice in homes at varying energy efficiency targets. Is this a missed opportunity for builders in meeting the growing energy efficiency desires of buyers -- an increasing number of whom self-identify as sustainable consumers? Perhaps. Research from McGraw Hill Construction shows that 73 percent of home buyers are willing to pay more upfront for green home features, like energy efficiency. How much more? According to the Green Building Advisor, the most common estimates are 1 to 3 percent.  In that HERS scores are the equivalent of a miles-per-gallon ranking for home performance – the lower the score the better -- a lower HERS score means reduced home energy costs for homeowners. Homebuyers might be willing to pay more if they thought they’d get more, in terms of energy savings. Take this as an example:

• HERS score of 65. This is often about level offered by builders as energy efficient. This could be the baseline or “good” efficiency package.
• HERS score of 40. A home at this level would likely be net zero energy ready, meaning it is super-efficient and can become net zero by integrating solar or other onsite renewables. This would be the “better” efficiency package.
• HERS score of 0. This is a net zero home. This would clearly be the “best” package a homebuyer could opt for.

Homebuyers are familiar with the package approach, though it remains to be seen how much they’d be willing to pay for HERS scores at different levels. What is indisputable is that the integration of good design and construction plays a major role in determining energy performance, something architects are increasingly advocating.Evaluating the Good, Better, Best ApproachEmily Mottram is the owner of Mottram Architecture, a full service architecture firm specializing in energy efficient design and Net Zero construction in New York, Pennsylvania and Maine. Her seven-year-old company also offers energy consulting, energy audits, HERS ratings and consultation on building envelope design. Mottram’s clients are typically driven by the dual desire for sustainability and energy efficiency but the option of offering a “good, better or best” performing home – reaching a specific performance target or HERS score at an incremental price increase that the buyer would be willing to bear, is in her opinion, a largely untested concept.“I’ve recently been discussing the idea of a ‘pretty good home’ with some building industry colleagues and there’s a definite awareness that a HERS 60 home, for example, could be an acceptable target for one buyer, while only a Net Zero home would work for another,” Mottram said. Offering homes in specific HERS target ranges could hold appeal for a certain segment of homebuyers willing to pay more upfront for more comfortable homes with lower utility costs.  This could be a win-win for customers and builders who can offer more targeted options to meet customer needs. Regardless of the target, Mottram says that architects and builders can do a number of things that will increase home efficiency and help lower overall HERS scores and many are inexpensive or have relatively low incremental costs.Integrating Good Design, Construction Practices“One trick that literally costs nothing is the orientation of the house,” she said. “Using the sun for its heating potential and reducing North windows will ultimately save consumers money on energy costs.” Mottram notes that increasing the focus on the thermal envelope – particularly installing good air barriers, taping and sealing in the right locations, can dramatically improve the energy performance of a home. In addition, increased insulation -- R21-40 walls -- offers significantly higher energy performance. “Also, reducing the framing and having a tightly sealed envelope allows for more insulation and pays for itself in no time.  “Simply maximizing the placement of windows -- these are all things that can boost energy efficiency,” she added.“By focusing on good design and construction practices, you can get a better performing home for reasonable incremental cost, but the design has to focus on proper construction and air sealing, which is why building science education, is so important,” she said, adding that regardless of the energy performance target, builders must increase their knowledge of building science and its impact on energy performance. “It does require a little more though from the builder to use less framing and increase insulation values. It takes more skill to follow through with contractors on the air sealing, air barriers and doing it all in the right locations, but this is ultimately how you maximize home energy performance, regardless of what the HERS score target might be.”Where Best Practices and Energy Upgrades IntersectBuilders will need to determine consumer willingness to pay for energy efficiency at various cost levels to determine if an “energy upgrade” approach makes sense. However, from a practical standpoint, builders would need some commonality, across upgrade options, to make the building process for homes of different efficiency levels feasible. The best way to do that is to have some energy efficient best practices that are undertaken on all builds, for example advanced framing, raised heel trusses, approaches to air barriers and sealing, things that impact the overall design and build process. Other items, like water heating and lighting efficiency, are more easily adjusted with less impact on the build process or other building systems. This would also help drive down the incremental costs for efficient building, improving the consumer return on investment. It is hard to say if energy upgrade packages are part of the future of housing, but if they are, they will be enabled by a broader, baseline level of energy efficient building practices.