The value of energy efficiency is the most overlooked and misunderstood part of building a new home. Even most home builders don’t understand it thoroughly. With interest rates around 4%, you currently pay only about $5 for every $1,000 borrowed for a new home. Therefore, if a builder is skilled enough to be able to spend $5,000 (costing you $25 per month) to save $50 per month in utility bills, they are creating $25/month savings for you. Especially since utility bills are constantly increasing and your payment stays the same. When done right, an energy efficient home is also much healthier and more comfortable than a standard built home.
One way to test the energy efficiency home is a blower door test. A blower door test measures air infiltration or draftiness. An air tight house is also a water tight house. The total volume of air in a typical home is exchanged with outside air and the accompanying allergens and pollutants several times a day. The best practice is to get your home so tight that mechanical air exchangers are needed to bring in fresh air at a controlled location and controlled intervals with a heat exchanger and advanced air filtration.
There are several construction methods that can be used to increase the overall tightness and energy efficiency of a new home. One of these methods is to use raised heel trusses. Raised heel trusses allow increased insulation at the vulnerable point where the trusses narrow down to a point over exterior walls. Since lumber has a much lower R-value than insulation, thicker walls with fewer studs are preferred. The quality and efficiency of doors and windows as well as the type and thickness of insulation is a critical element of energy efficiency.
Another important consideration is the HVAC system in the home. A high efficiency furnace is important but only if it is right-sized. The goal is to make the home so efficient that it can be heated by a much smaller furnace. Duct work should be engineered to deliver the proper volume of air to each room given the room’s size, window area, and solar orientation. The net effective length of ductwork can be shortened by improving air flow with the use of turning veins, radius turns, and 45 versus 90 degree corners. Still, all these items have little effect if the furnace and ductwork are not sealed air tight so that conditioned air is not lost into the mechanical room or inside the floor or attic.
When building your new home, keep in mind the benefits of some of these construction methods as the benefits and the savings they provide outweigh the cost and will add value and life to your new home.