Photo of a brightly lit, modern kitchen in a new, energy-efficient house.

Photo by Sidekix Media on Unsplash

You’ve started looking for your next house, meaning you have several important decisions.

You must determine how much square footage you want and the number of bedrooms and bathrooms.

You also want to pay attention to the age of your soon-to-be home. But also, is a newer home more energy-efficient than an older one?

New houses are more energy efficient thanks to improvements in Energy Code Regulations, which have driven improvements in insulation, the quality of windows and doors, and the sustainability of building materials. As a result, new houses are more airtight and thermally efficient than older homes.

This article will discuss why a new home (versus one built 20 or 40 years ago) is greener.

We’ll also discuss whether an energy-efficient home is more expensive, so make sure you keep reading!

What Makes New Homes More Energy Efficient

According to Energy Star, if your home was built in 2000 or after, it will be larger than homes built before that year. How much larger? Up to 30 percent!

This alone would suggest that newer homes are less energy-efficient, since they require more building materials. Yet today’s houses are greener than ever.

A combination of new energy-efficient code requirements, superior insulation, and more sustainable building materials contribute to much more energy efficient new home construction.

Add to this the utilization of renewable energy sources, such as solar PV, and you’ve got the makings of a new home that’s much more energy efficient.

Let’s take a closer look at the sustainability areas prioritized in new homes in the next section.

Energy Efficient New Home Construction

Recent Energy Code Regulations

Energy codes are part of the Building Energy Codes Program (or BECP) as created by the U.S. Department of Energy (or DOE) in 1991.

The DOE partners with local and state governments to assist in the adoption of new, more eco-friendly energy code rules. The DOE does this in conjunction with the National Association of State Energy Officials (or NASEO) and the Regional Energy Efficiency Organizations (or REEOs).

In short, energy code regulations are established on a state-by-state basis. Thus, they can and do vary, depending on where in the country you live. For example, as of 2020, the Title 24 regulation in California mandates that new homes in the state have solar panels.

In New York, the energy program known as NYStretch was designed to increase energy savings in the state by 11 percent in 2020.

Some states change energy code regulations often, and others seldom. Georgia, in 2020, updated its energy code for the first time in nine years.

Although energy code regulations are a mixed bag, here’s what we know for sure.

Newer homes will follow more current energy code regulations than homes built 20 or 30 years ago.

You can use California homes as an example. Homes built in that state from 2020 onward will all have solar panels, while homes built before then might not. 

Improved Insulation

Another factor that makes a home energy-efficient is insulation. And not all older homes even have insulation. Those that do might not use the most eco-friendly insulation options.

According to insulation company USA Insulation, homes built in the 1960s featured cellulose or fiberglass insulation.

If you’ve ever seen a home that’s cotton candy pink once you remove the walls, this is fiberglass insulation from back in the day. Whether it was installed as batts or blankets, fiberglass insulation is only moderately effective at insulating homes.

Picture of the attic floor in our first net-zero project home in Florida, covered in pink fiberglass insulation--better than nothing, but not as energy-efficient as it could be.
Yep, we found that old familiar pink fluff in the attic of our first net-zero renovation.

Cellulose is more efficient than fiberglass. But one of the best kinds of insulation today is spray foam.

Unlike blankets and batts, which have limited applications, spray foam insulation can reach into tight corners, uniquely shaped crevices, and other areas that are less accessible.

We talked more about insulation in this post, so go ahead and give it a read if you missed it.

Comparing the R-value of older insulating methods, such as fiberglass, to spray foam insulation would reveal a big difference in energy efficiency.

While even a little insulation is better than none, today’s advancements in insulation allow today’s homes to be even greener than those built before these newer insulation methods existed.

Safer and More Sustainable Building Materials

Home construction has evolved and will continue to evolve as the years go by. Through trial and error and testing, homebuilders learn which materials are durable, safe, and energy-efficient and which aren’t.

Part of this innovation has arisen out of consumer demand. While people have always cared about the environment, there wasn’t as much focus on it 20 or 30 years ago as today.

According to Solar Panel Authority, solar panels weren’t widespread in homes until 2015, which is a case in point.

Here’s another example. Outside of its energy efficiency, modern insulation is also a lot safer.

Fiberglass and cellulose insulation came into being because homebuilders needed an alternative to asbestos. Yes, that’s right, before the 1960s, asbestos was used for home insulation. (It was also popular in the popcorn ceilings of the ‘60s and ‘70s.)

As you can imagine, that didn’t last long! Still, if the home you’re looking at is more than 50 years old, you want to know what insulation material it uses. This is for your health, as exposure to asbestos can be deadly, and having it safely removed is expensive.      

Another potential hazard common in older homes is lead paint. Especially if you have kids (or plan to), you need to know if lead paint is present in a home you buy. You need the plan to get it taken care of if it’s there.

Besides the absence of dangerous materials like lead or asbestos, today’s more progressive new homes may include sustainable building materials that the homes of yore would never have.

For instance, instead of wood, modern homes might feature bamboo. Wool insulation is a natural replacement for fiberglass.

Recycled materials are also making their way into new homes—insulation made from old jeans or countertops made of recycled paper are just two examples.

Rammed earth for floors or walls is also becoming trendy these days, although you won’t likely see this in new homes unless you’re getting your own built and ask for it specifically.

This eco-friendly material has great thermal properties. It will hold onto the sun’s warmth during the day and then release it at night. 

New Windows and Doors

All homes have windows and doors, but the way the technology has evolved in decades past is another reason why new homes have the energy efficiency advantage.

Double-paned or triple-paned windows are not something you’ll see in homes from 40 or 50 years ago.

Low emissivity or low-E glass coatings are also a newer advancement. A low-E coating reflects infrared light from the sun to keep the rooms in your home at a consistent and comfy temperature.

Photo of our first net-zero project house in the process of having windows replaced. One large window opening is empty and the new, energy-efficient windows are resting on the ground in front of the house.
Windows were at the top of our to-replace list when we renovated this 1980s house in Florida. With a newer house, you might not need to worry about replacing windows right away.

Interior and exterior doors have also become greener through materials such as steel, vinyl, and fiberglass.

If you tour a couple of old homes, you’re not likely to come across those three materials in any of the doors. We’d bet that besides the exterior doors, all are made of wood, right?

Wood doors are moderately energy efficient, but the benefits are negligible compared to fiberglass doors especially.

New windows and doors also have tight seals and weatherstripping that prevent outdoor air from entering the house and indoor air from leaking.

Older homes can have new windows and doors installed that increase their energy efficiency, but due to the price of this endeavor, you’re just as likely to see an old home with equally old windows and doors.

Does More Energy Efficiency Mean Higher Home Prices?

Now that you better understand what makes today’s homes the more eco-friendly option for homebuyers, you probably want your next home to be newer. Does this mean you’ll have to increase your budget?

Yes, but perhaps not by as much as you’d think.

Energy resource RMI examined the costs of standard homes versus zero energy homes or those designed with energy efficiency in mind. The price gap between these two housing categories used to be huge, but it’s gradually narrowing.

However, you will likely still spend more money to own a newer home for two reasons, neither of which is related to energy efficiency.

The first reason is that in a new home, all the building materials are fresh and will be for years to come. The appliances, insulation, flooring, basement, and attic are also brand new.

They’re higher in quality than a weathered 30-year-old home (unless it was kept in immaculate condition).

Since the newer home is of higher quality, its asking price will likely be higher as well.

The second reason newer homes cost more is due to size. As we mentioned earlier, Energy Star stated that today’s home is 30 percent bigger than homes built before the year 2000.

The greater the square footage a home has, the more expensive it usually is. But if you can renovate an older, smaller home, the end result will be an overall more eco-friendly dwelling.

Final Thoughts On New Construction Energy Efficiency

Newer homes are more energy-efficient than older ones due to the use of more sustainable building materials, more eco-friendly doors and windows, better insulation, and continued changes to energy code regulations.

Photo of solar technicians installing solar panels on the roof of our energy-efficient net-zero renovation house in Florida, with extra panels resting against the side of the house.
Improvements like air sealing, insulation, and windows bring energy needs down. After that, adding solar panels makes it easier to provide your own energy.

If an older home is all your budget allows for, you can always make your home greener by adding solar panels, instituting air leakage safeguards, upgrading to Energy Star-rated appliances and windows, and getting new insulation.

When you make those upgrades, your old house will likely be more energy efficient than the newer houses you didn’t buy. And that’s a win for you and the earth.

Check out this article for more information about how energy efficiency measures impact home resale values!

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