hvac system efficiency vs whole home efficiency

Home efficiency vs. HVAC system efficiency

What can a homeowner do to improve energy efficiency and lower energy bills

We have talked a lot about HVAC unit efficiency and indoor air quality. We have also touched on HVAC myths, fables, and hidden truths. One thing we have not discussed in depth is home efficiency vs. unit efficiency, so let’s do that today.

You can have the highest priced, highest SEER unit under the sun, but if you do not have an efficient house to back it up, you could be losing money. In this blog post, we are going to discuss what you can do to improve the efficiency of your house and lower your bills for the long term.

There are many percentage loss calculators, and every house is different, but on average the break down goes something like this:

  • 35% of heat loss is through the walls in a home.
  • 25% is through the roof. This is very noticeable in winter when many houses have frost or snow on the roof. The houses with extreme heat loss are easily identified by the wet shingles where snow has melted away due to lost heat through the roof. That is NOT a sign of a healthy home.
  • The remaining 40% is lost through doors, windows, and the floor.

Many people hear these percentages and start stressing, thinking they need to change everything right now. But this is not the case. You can tackle these projects for your home over time, and make a big difference with each step you take. Any step forward in home efficiency is a good step forward!

Let’s break it down and see what we can do.

Windows and Doors (40% of Heat Loss):

One of the biggest ways to update your home and boost its efficiency almost overnight is by replacing the windows and doors. We have come a long way from the wooden chiseled, single pane, uninsulated, extremely drafty windows that we all grew up with. Walking past these windows on a winter night left you instantly chilled to your core! These days, windows are much more efficient, come in an endless variety of styles, and are affordable with many financing options available. You even have the option of a quadruple pane window now! And who doesn’t want to replace their 15-year-old door for one with more curb appeal and less heat loss?

For these types of projects, you can typically get free cost estimates from contractors, and most are willing to work out a deal.

Home Insulation (35% of Heat Loss):

One of the biggest enemies for a home and its HVAC efficiency is the wall insulation. Many will automatically assume that attic insulation is the culprit. While that’s definitely part of it, on average your bigger enemy is the wall and crawlspace insulation. You can attack this challenge in many ways though:

  1. You can have your siding pulled and have an insulation like Tyvek laid over the exterior of your house. You do not need to have your siding completely redone and most contractors are completely capable of a project like this.
  2. Spray foam insulation is one of the best new pushes over the last ten years and the results are incredible. Every contractor has a different approach, and there are a variety of options. Just like with windows and doors, you can often get free quotes from contractors, so don’t be afraid to reach out and see what they can do!

Roof Insulation (25% of Heat Loss):

When it comes to roof insulation, we have to take into account more than just the insulation in your attic. There is no doubt that has a big part to play, but most people forget that the shingles on their roof, their decking board, and the insulation laid for the shingles also serve an important role in keeping your house well insulated.

If you have a basic single layer of the 3-tabbed shingled roof then you most likely have the original style of roof insulation which is nothing more than a thin sheet of felt paper. Roofing manufactures like GIF will not even warranty their shingles anymore if you use that stuff under their materials. Insulation in roofing materials has drastically improved from where most homes were just 10 years ago.

It’s likely that at least one of the efficiency issues described above applies to your home, which means it’s time to look into updating your house. As we said above, you can get a lot of estimates for free so shop around and get yourself the best price! Most contractors are excited to take on a home efficiency project, so reach out today. And remember: even just one step forward is a good step forward!


If you need any help with your HVAC system then give us a call today on (703) 670-8519 or get in contact with us online.


Check out our other blogs for some great HVAC advice: