New home buyers, especially those that are purchasing pre-build, have a lot of choices to make during construction. Everything from what type of flooring to install to what color shingles for the roof may be decided. But often, one of the most important decisions that can be made is overlooked: the quality of the home’s insulation.
Improving Insulation R-values can Reduce the Required HVAC System Size Needed
HVAC systems are designed to maintain a constant temperature inside a given home’s thermal envelope. Therefore it stands to reason that if the thermal envelope is better insulated, the required HVAC system size will be smaller. This can save the homeowner money on energy costs for the life of the home, not to mention the savings that come from installing a smaller system to begin with.
For example, in the images below are two heat load calculations done on exactly the same 2,500 square foot home. Every variable is exactly the same: same number of people, same appliances, same windows on the same sides of the home. The only difference is that in the first example, standard insulation values are used. These are R-13 insulation in the exterior walls and R-30 insulation in the attic. To keep things simple a house built on a concrete slab was used. As the heat load calculation shows, the required tonnage for this home in example A is 3.90 tons, or what would be a four ton system.
For example B, the exterior wall insulation is R-15, with an additional R-2 board insulation installed between the studs and the brick finish, and the attic insulation is R-56 with a radiant barrier installed on the underside of the roof decking. As this heat load calculation shows, the required tonnage is now only 3.49 tons, or a 3.5 ton system.
These two examples are both done with regular insulation, such as fiberglass batting or blown cellulose. In today’s market there are even better options available, such as sprayed foam insulation that not only insulates, but also seals the thermal envelope as it’s applied, and can actually add structural strength to the home as well.
Smaller HVAC Systems Cost Less to Install, and Use Less Energy to Operate
Reducing the size of the HVAC system can save money in two ways. First, during the initial install the smaller system will usually cost less. Then, over the life of the system it will use less energy than the larger system. The second benefit is a permanent one, in that it will always cost less to maintain a constant temperature inside a better insulated home than one with standard insulation.
Of course, increasing the insulation R-value in a new home will cost more money up front, but with a guaranteed lifetime benefit, in the long run it will cost less and less. After all, energy prices rarely if ever go down, and using less energy will always be cheaper than using more, no matter how much it costs.
Increasing Insulation R-values Can Make the New Home More Comfortable
An added benefit of improving the insulation in the home is that it will be generally more comfortable. This is because, with better insulation, the home won’t gain or lose heat as rapidly, which will cut down on hot or cold spots inside the thermal envelope.
Anyone buying or building a new home should do their own research to help them decide whether investing in higher R-value insulation would be right for them. In today’s economy, it’s one of the few things that have an almost certain guaranteed return on investment.
Barrett James, Jr. - Barrett James, Jr. is the author of the sci-fi novel, "The Legacy of Balthazar" as well as many self-help articles about the HVAC ...
