Most resale homes: over 100
Older homes were built before modern energy codes, and most score well above 100, often 120 to 140. Leaky ducts, thin insulation and older equipment all add up.
Buyer guide · Energy efficiency
What a HERS score is, and what it saves you in dollars
Every Insight home is tested and scored on the HERS Index. Here's what the number means, how it compares with the homes you're touring, and how to turn it into a monthly energy bill you can plan around.
Think of it as miles per gallon for a house, scored like golf
The HERS Index (Home Energy Rating System, run by the national nonprofit RESNET) is the industry standard for measuring how much energy a home needs. It works like a car's MPG rating, with one twist: lower is better, like a golf score.
- 100 is the benchmark: a home built to the 2006 national energy code.
- Each point is about 1% of energy use. A home that scores 70 uses about 30% less energy than the benchmark; a score of 50 means about half.
- A score of 10 means a home uses roughly 90% less energy than the benchmark home.
- 0 is a net zero energy home: over a year, it produces as much energy as it uses.
- 10–20Ultra-efficient Insight home
- ~60ENERGY STAR home
- ~100Standard new home (2006 code)
- 120–140Typical resale home
Lower is better. Scale based on RESNET data and Insight Homes' published scores.
How the homes you're touring compare
The average new home: about 55
According to RESNET's 2024 data, the average newly rated home scores about 55, roughly 45% more efficient than the 2006 code home. Today's codes are better, but most builders stop there.
Insight homes: often about 10
Insight's published plan scores run from 5 to 26, and many homes score in the teens. That's 80 to 90% less energy than the benchmark, and over five times more efficient than a typical new build.
Why Insight homes score so low
A low score isn't one feature; it's the whole house working together. Every Insight home includes the building science that drives the number down:
- An airtight, well-insulated shell: 2x6 walls with R-23 dense-pack insulation, R-49 in the attic, a sealed and conditioned crawlspace, and two rounds of air sealing.
- Windows that block 90% of the sun's heat (Super Low-E), so the air conditioner works less in a coastal summer.
- Efficient equipment: a variable-capacity inverter heat pump up to 20 SEER, tankless hot water and ENERGY STAR appliances.
- Owned solar: a 5,000-watt solar system on every home produces part of your electricity.
- Fresh, filtered air: a fresh-air ventilation system and MERV-13 filters, because a tight house needs to breathe on purpose.
See the full list in what's included in an Insight home.
Tested by an independent rater, not just promised
Anyone can say a house is efficient. A HERS score is measured. On every Insight home, an independent, certified HERS rater reviews the plans, inspects the insulation before the walls are closed, and tests the finished house with a blower door (to measure air leaks) and a duct test (to make sure the air you pay to heat and cool actually reaches your rooms). Your score is based on those tests.
What it saves in dollars
Estimate your energy bill in a lower-HERS home
Because each HERS point is about 1% of energy use, you can roughly scale what you pay today. Enter your current average monthly gas and electric bill and your home's score (if you don't know it, most resale homes are 120 to 140).
A rough illustration, not a guarantee. HERS scores model heating, cooling, hot water, lighting and major appliances under standard conditions; your actual bills depend on the size of the home, how you live, the thermostat, the weather and utility rates. Insight's scores reflect standard plans modeled by an independent certified rater, and actual scores vary by home. Delmarva Power and natural gas or propane rates change over time.
Real bills from Insight homeowners
“We have lived in our Whatley model for 20 months and the average of our gas and electric bill is only $112.”
The Brown Family, Whatley homeowners
“July was an extremely hot month and when we got our electric bill it was $87. I called up the electric company to confirm it was a full month's bill which it was.”
Ron & Dignora B., Cartwright homeowners
From Insight Homes homeowner reviews. Individual results vary.
Why it matters beyond the bill
- Comfort: no drafty rooms or hot upstairs bedrooms. The same tight shell that saves energy keeps temperatures even.
- Quiet: dense insulation and tight construction keep outside noise out.
- Healthier air: filtered fresh air and fewer leaks mean less dust, pollen and humidity.
- Budget certainty: lower, steadier energy costs make the true monthly cost of the home easier to plan. Try the payment calculator to see the whole picture.
Questions to ask any builder
- What is the HERS score of this plan, and who tested it?
- Is every home tested, or only a sample?
- What were the blower door and duct leakage results?
- Is solar included, and is it owned or leased?
Every Insight floor plan shows its published HERS score. Want to see the difference in person? Schedule a tour and I'll show you what's inside the walls.
Let's talk
Questions about your new home?
Ask me anything about building or buying new in Southern Delaware. I'll give you a straight answer and help you find the right community and plan.
