8 Best Building Materials for Energy-Efficient Houses

Giovanni Valle is a licensed architect and LEED-accredited professional and is certified by the National Council of Architectural Registration Boards (NCARB). He is the author and managing editor of various digital publications, including BuilderSpace, Your Own Architect, and Interiors Place.

Energy-efficient homes have made the news again and again. They are loved for their ability to save you money and save the environment. If you want to build an energy-efficient home, you’ll want to use specific materials.

The best materials to use to build an energy-efficient home include rammed earth, straw bales, and recycled steel. There are also types of insulated concrete that provide excellent heat retention. Another “industry best” is the installation of a cool roof, especially when combined with solar panels.

In this article, we will examine the 8 best materials for energy-efficient homes. These include the materials listed above, and more. We will discuss why these materials are so efficient, what constitutes an energy-efficient home, and the pros and cons of choosing one.

What Defines an Energy-Efficient Home

An energy-efficient home does not have to have solar panels or a rainwater cache; there are no extreme boxes that a home needs to check to be considered energy efficient. The measurement of home efficiency is less of a checklist and more of a sliding scale.

In fact, the US Department of Energy created a Home Energy Score. This is an interactive report that allows you to determine your home’s energy efficiency on a scale from one to ten. The average home in the US scores a five on the scale.

The report takes into consideration the following factors:

Airtight construction
Air-sealing around windows, doors, outlets, and vents
High-performance or Energy Star windows
LED or Energy Star Lighting
Energy Star Appliances
High-Performing or Energy Star home heating and cooling systems
Better insulation in basement, attic, walls

Once you have your score, the US Department of Energy can give you recommendations on how to improve your score, save more money, and make your home more energy-efficient. You can get a jumpstart on this score by using the energy-efficient materials below.

Solar Panels

Solar panels are the layman term for something called a PV Panel, or a photovoltaic system. What this is, is a panel with a collection of cells that absorb sunlight, and with it, generate current electricity, which we use in our homes.

The first commercial solar panel was invented in 1881 by Charles Fritts. This may seem hard to believe, considering they didn’t truly catch on until over 100 years later. Though Charles Fritts created the first commercial solar panel, it wasn’t very efficient. Almost everyone forgot the solar panels in favor of coal-fired power plants.

Russel Ohl was the one who improved upon the solar panel and patented his modern design in 1941. This is the same basis for the solar panels we use today.

What makes solar panels so attractive to add to your home is the amount of electricity they make. In the summer, solar panels can provide 100% of the electricity needed to power your home and heat your hot water, depending on where you live. In the winter, this may fall to 25%.

You may be asking, “What about when it’s dark out?”

There are two main ways for your house to have power when it is dark out. One of them uses electricity from the city grid and one that uses energy stored in a battery.

Grid-Connected System

If you install solar panels and choose to operate on a grid-connected system, your home will be able to use the electricity provided by the local utilities when it doesn’t have its own power.

One of the most attractive features you get with a grid-connection is a net-metering system. What this means is that when your solar panels are producing more energy than your home needs, the excess energy will be sent back to the grid to provide power to other people. To pay you for this power, utility companies provide you with a credit.

This credit will help pay the power bills for the times you are using grid power.

Off-Grid System

With an off-grid system, your home doesn’t have any access to public utilities. To compensate for the literal dark times, or winter season that doesn’t get as much sun, most people install power banks. These are essentially large batteries that store surplus energy throughout the day and year and send it back to your home when needed.

This may seem like a great way to save money, but unfortunately, the power banks are expensive to install initially.

Cool Roof

A cool roof is one of the easiest ways to increase the efficiency of your home. It can be installed on almost any roof type, without the need for massive construction or renovation. A cool roof is a roof that has been designed or altered to reflect the sun’s heat.

This reflective ability means that instead of absorbing the heat from the sun and transferring it into the home below, it reflects the heat away from the home. A cool roof can be up to 50° F cooler than a dark roof in the same conditions.

Cool roofs are energy efficient because they decrease the internal temperature of your home, and therefore allow you to save money and energy on air conditioning in the summer.

To create a cool roof, most roofs don’t need to be replaced. According to Energy Saver, there are many options to create a surface that will transform your roof into a cool roof. This includes coating it with a “highly reflective type of paint, a sheet covering, or highly reflective tiles or shingles.”

Rammed Earth

One of the most stylish ways to make your new home energy efficient is by building it out of rammed earth. Exactly as it sounds, rammed earth is a way to create walls using dirt, and compacting it.

If building a house out of dirt sounds slightly archaic to you, then you’re spot on. Rammed earth homes can be found around the world, on every continent – other than Antarctica.

The process of building a rammed earth wall is by building barriers, much like concrete forms, that stand upright and have a space between them. This space is then filled with dirt that is compacted to 50% of its size. The process is repeated until the forms have been filled, and the wall is sturdy.

Historically, this compression was done by human muscle, but in modern days the process is much simpler and done with pneumatic pressure.

Rammed earth walls have many excellent perks:

High thermal mass. Meaning they absorb heat during the daytime, and release it at night.
Regulate humidity. Rammed earth walls can keep a home between the ideal 40-60%.
Easily repaired. By using the original sand mixture to patch and smooth dents.
Original design. Not only is each rammed earth wall unique, but you can also create patterns throughout the layers of compression.
Lower cost. The materials used to create rammed earth walls are lower than other methods of building homes, though the labor may be more intensive.

To see an example of a beautiful rammed earth home, watch the video below:

Insulated Concrete

Insulated concrete is another way to make your home more energy efficient when building it. Insulated concrete consists of poured-in-place concrete walls that are sandwiched between two thick layers of insulation. These layers of insulation are left in place permanently.

The insulation layers are usually made of a thick foam that increase airtightness, and therefore air efficiency. Some estimates of power saved on the heating and cooling of buildings have come in at an impressive 20%.

Insulated concrete also withstands natural disasters like earthquakes much better than traditional homes. They also lessen noise transfer immensely, and serve to limit the possible infestation rates of bugs and vermin.

Not only are the foam walls difficult and unappealing to these pests, but the concrete also stops them from setting up camp in your walls. Common wood and drywall homes have spaces in between the interior and exterior walls, and often face issues with rat and termite infestations.

Recycled Steel

According to the Steel Recycling Institute, “Steel is the most recycled material on the planet, more than all other materials combined. Steel retains an extremely high overall recycling rate, which in 2014 stood at 86 percent. The amazing metallurgical properties of steel allow it to be recycled continually with no degradation in performance, and from one product to another.”

This information should already explain a large reason why using recycled steel is so energy efficient. Not only does it save new materials from being produced, but it can be recycled in the future if your home ever needs to find a new life.

As steel is so strong, it can support large layers of insulation without having to worry about the structural integrity of your home. Better insulation allows your home heating and cooling systems to work less because there is less air transfer between the indoors and outdoors.

Steel also does not tarnish, mold, or rust like other metals. There are no special treatments required to keep steel operating at its best level, and it only needs for you to bring it into your home.

Straw Bales

Straw bale homes have been built for thousands of years. The simplest version of these homes is to take blocks of straw and build walls out of them. These were the first versions of straw bale houses. They were extremely rudimentary and came with some real dangers: highly flammable, rodent infestation, and prone to rot.

Luckily, the straw bale structure kept developing, and now it is one of the most unique ways to create an energy-efficient home.

Modern-day straw bale homes involve a process similar to others on our list. The walls of these homes consist of filling plaster frames with dry straw, using the plaster as the structural forms, and the straw as the insulation.

What makes these walls, so energy efficient is the great insulation power of straw. This will lower the heating and cooling costs of the home. The straw itself is also readily available and is a sustainable resource.

The clay walls also lend a unique look to your home, and no two straw bale houses could possibly be the same.

High-Performance Windows

According to the US Department of Energy, “Heat gain and heat loss through windows are responsible for 25%–30% of residential heating and cooling energy use.” That means a quarter of all home energy use is caused by outdated or cheap windows.

If you are building your own home or considering new materials to increase the energy efficiency of your current one, then look for ENERGY STAR rated windows. This is a label created by the National Fenestration Rating Council of the USA. Any window or door with an ENERGY STAR label will be energy efficient.

Within these ENERGY STAR rated products are a more detailed list of criteria. This is found on the NFRC Label on each product. This label scores each product on the following criteria:

Criteria	Description	Rating Range	Look For
U-Factor	measures how well a product can keep heat from escaping from the inside of a room. The lower the number, the better a product is at keeping heat in.	0.20–1.20	Low numbers
Solar Heat Gain Coefficient	measures how well a product can resist unwanted heat gain, which is especially important during the summer cooling season. The lower the number, the less you’ll spend on cooling.	0-1	Low numbers
Visible Transmittance	measures how well a product is designed to effectively light your home with daylight, potentially saving you money on artificial lighting. The higher the number, the more natural light is let in.	0-1	High numbers
Air Leakage	measures how much air will enter a room through a product. The lower the number, the fewer drafts you’ll experience.	≤ 0.3	Low numbers

Bamboo Plywood and Hardwood

If you haven’t been convinced with the rammed earth, straw bale, or insulated concrete walls, then maybe you can be swayed to at least choose bamboo as a building material. Bamboo has long been considered a weed, but while it is actually a type of fast-growing grass, it acts more like a wood when used in our homes.

Currently, the building sector is responsible for 30-40% of all carbon emissions. If we turn to bamboo instead of traditional wood, we can lower this number greatly. How? Because bamboo is a highly renewable resource.

It grows rapidly, so rapidly, you could see it with the naked eye. Bamboo grows one millimeter every 90 seconds, which means it replenishes at a rate that trees could never dream of. In fact, because it can be harvested annually, and self regenerates, it produces 25 times more usable material than hardwoods.

Bamboo also has the following amazing benefits:

Produces up to 35% more oxygen than hardwood trees
Filters 4 times more carbon dioxide out of the air
Is naturally pest-resistant
Easy to source
Bamboo plywood is easy to maintain
Is up to 3 times firmer than common hardwoods
Especially well suited to humid environments like bathrooms
Is 100% usable, even in human diet

The Perks of Going Energy-Efficient

There are some fantastic benefits of building an energy-efficient home using the materials above:

You can receive tax breaks of up to 30% on ENERGY STAR rated systems.
You can also receive credit from local utility companies by selling them the excess power your solar system creates.
Experience less stress and lower mortality by giving back to the world. Choosing to build an energy-efficient home may provide you with a more meaningful existence. You may feel more connected to the world around you because you are making an effort to change it.
Building an energy-efficient home now can also increase your resale value in the future. Adding ENERGY STAR, or LEED ratings to your home may allow you to increase your asking price. Not only because of the investments you’ve made in the energy-saving products, but your home will meet the building standards that will increase in the future.

The Problems With Converting to Efficient Energy

While building an energy-efficient home is the right thing to do, it may not be the easiest thing. There are two main drawbacks to building an energy-efficient home:

Increased cost. Though an energy-efficient home will save you money in the long run, the investment you need to pay upfront is steep.
Longer build times. Certain energy-efficient materials, like rammed earth walls, can increase the construction timeline of your new home.

Summary

The world needs humans to make an effort to correct years of mistakes and harmful wrongdoings to the environment. You can do your part by choosing to build an energy-efficient house. Though it may cost you more money upfront, the moral and financial incentives are great, as well as the long term effect on the environment.

Plus, many of the materials listed above are more durable than their non-efficient cousins. That means that your house will be standing for years to come, and so will planet earth.