G3. Big Green

The debate over building energy codes, and energy efficiency in general, often centers on upfront cost. But energy efficiency more than makes up for that incremental cost with longer-term savings that add up over time, like the power of compounded interest.

A recent Department of Energy (DOE) release estimates that adopting the 2024 International Energy Conservation Code (IECC) would increase residential construction costs by $9.2 billion annually, or up to $14,000 per home. Rather than focusing on the headline figure alone, it is useful to examine the estimate in the context of overall home costs and long-term homeowner economics.

Put the cost in context

Since the IECC is an energy code for residential buildings, let’s focus on single-family homes. Adding multifamily homes would only strengthen the following cost argument.

The U.S. builds roughly one million new single-family homes each year. Spread across those homes, DOE’s $9.2 billion figure implies about $9,200 per home.

Now compare that to actual home costs. Using data from the National Association of Home Builders (NAHB):

• Average construction cost: $428,000
• Total price including land and soft costs: $665,000

That means that the  $9.2 billion headline represents:

• 2.15% increase relative to construction cost
• 1.38% increase relative to full home price

In other words, even under DOE’s assumptions, energy codes raise total home costs by around one to two percent. That is small relative to normal year-to-year swings in material costs, interest rates, or land prices.

It is also far below the $31,000 figure often cited in industry testimony.

What do homeowners get in return?

The key question is not cost alone. It is cost versus savings.

DOE’s analytical framework recognizes this. It evaluates:

• upfront incremental cost
• annual energy savings
• payback period
• life-cycle cost over a 30-year mortgage
• annual cash flow to the homeowner

This matters because homeowners do not experience costs in isolation. They generally experience monthly cash flow. Lower energy consumption can also improve long-term affordability by reducing exposure to future energy price volatility while supporting a more efficient and reliable energy system.

Independent analysis from Pacific Northwest National Laboratory (PNNL) shows that the 2024 IECC:

• reduces household energy costs by 6.8% on average
• produces positive cash flow in year one
• yields about $144 in net savings in the first year

Even if the upfront cost were $9,200, the structure of mortgage financing means:

• the incremental monthly mortgage cost is modest
• energy savings offset that cost immediately
• households come out ahead from the start

Looking Beyond Simple Payback DOE’s press release emphasizes long “payback periods,” suggesting some exceed 10 years. But simple payback may not be the strongest for housing decisions:

1. Because Most Homes are financed. Buyers do not pay $9,200 upfront in cash. They typically finance it over 30 years.
2. Cash flow matters more than payback. DOE’s methodology highlights “years to positive cash flow” as a key metric. = On that basis, IECC performs well.
3. Homes last decades. Efficiency improvements in the building envelope deliver savings over the life of the home, not just a short payback window.

Discussions about housing affordability often focus on reducing upfront construction costs. When asking how we can improve affordability for homeowners, an equally important consideration is the long-term cost of owning and operating a home. Building energy efficiency can help lower energy bills over decades, making it an important part of the affordability conversation.

As policymakers, builders, and consumers evaluate future building energy codes, the discussion should consider both upfront costs and long-term value. Looking at both sides of the equation provides a more complete picture of how energy efficiency can support housing affordability over the life of a home.

As energy demand continues to grow from new housing, transportation, manufacturing, and data centers, improving building efficiency can help reduce unnecessary energy demand while supporting affordability and system reliability. Using energy more efficiently remains one of the lowest-cost strategies for reducing waste and managing long-term energy costs.