The materials you choose for your home have a significant impact on heating and cooling costs. Prioritizing energy-efficient building materials and implementing effective design strategies can help reduce your energy consumption.
Materials with high thermal mass have the ability to store heat and re-radiate it at night, moderating indoor temperatures and reducing energy consumption. Concrete, stone, and brick have exceptional thermal mass properties.
Insulation
Insulation is one of the most important elements in reducing energy costs. It reduces the flow of heat into and out of a building, helping to maintain a comfortable temperature throughout the year. Depending on the type of insulation and R-value, it can lower heating and cooling costs by 10% to 50% or more.
There are several types of insulation material available for buildings, including fiberglass, mineral (rock and slag) wool, cellulose, natural fibers, and rigid foam boards and foils. The insulation R-value is a measure of its thermal resistance, or the ability to resist the flow of heat. It depends on the thickness of the material and its density, and can be affected by its age, moisture content and installation.
Many insulation companies promote rolled fiberglass because it’s the product they use the most, but blown fiberglass is often more cost effective and provides much higher R-values. It is also a more environmentally friendly option, but requires special equipment to install correctly.
Foam board insulation is usually made from polystyrene, polyisocyanurate or polyurethane and a blowing agent. Foam insulation can be installed in enclosed cavities such as walls and attics, or open spaces such as ceilings and roofs. It is also commonly injected into wall cavities. Foam insulation with reflective surfaces is referred to as radiant barriers and is most effective in hot climates.
Windows
Windows and doors are another major source of heat gain and loss in a home, and they can contribute significantly to your energy costs. Old or poorly insulated windows allow air to leak into your house and make your heating and cooling systems work overtime. Fortunately, you can reduce your energy bills with new, energy-efficient windows.
The best energy-efficient windows use a combination of advanced technologies to minimize heat transfer and provide a tight seal against drafts. They have double or triple glazing, Low-E coatings, and insulating gases between the panes. The gas fills, such as argon or krypton, lower the window’s U-factor and boost its insulation properties.
In addition to lowering your heating and cooling costs, energy-efficient windows improve indoor comfort, reduce UV exposure, and decrease reliance on non-renewable resources. The EPA’s Energy Star program provides ratings for products based on their performance in different climates and uses. These ratings are an excellent starting point when selecting materials for your home. Other ratings to look for include solar heat gain coefficient (SHGC) and air leakage. SHGC tells how well a product resists unwanted heat absorption, while air leakage is a measurement of how much conditioned or outside air seeps into a building. The higher the air leakage, the less efficient a product is.
Roofing
The vast majority of energy consumed in the average American home goes toward heating and cooling the house. And many of these energy costs are literally going through the roof. Inefficient and uninsulated roofing allows a great deal of heat to enter the home in summer, driving up air conditioning bills. It also lets a lot of warmth escape in winter, leading to astronomical heating costs.
For these reasons, homeowners should prioritize using energy-efficient roofing materials. In addition to reducing energy consumption and utility bills, these materials can also cut carbon emissions and contribute to environmental sustainability.
There are a variety of roofing options available, from traditional asphalt shingles to tile and even metal. One option that’s becoming increasingly popular is cool roof technology, which uses reflective pigments to keep the building cooler. Unlike conventional shingles, these new products typically don’t add much to the cost of the roof; they can pay for themselves in less than a year in hot climates.
Other energy-efficient roofing materials include stone and wood. These are abundant natural resources in Nigeria, and when used properly – for instance, in combination with a well-insulated envelope – can reduce energy use by lowering air temperatures. Additionally, they have thermal mass, which enables them to absorb solar heat in the daytime and release it during cooler evening hours.
Walls
Walls are one of the most significant contributors to energy consumption in a home. This is because they are responsible for blocking heat and preventing it from radiating outwards. Traditionally, walls are constructed from concrete and other materials that require large amounts of water for their production. This can put a strain on local water supplies and ecosystems. The use of more environmentally-friendly materials like rammed earth or aerated concrete can reduce the demand for water, while also improving the home’s thermal performance.
Another important consideration for selecting a building material is its ability to absorb and re-radiate heat when the sun is shining. Different materials have varying levels of thermal mass, and some will absorb the sun’s heat faster than others. These factors should be considered when choosing a wall material.
Trombe walls are a good example of how a wall can be used to reduce cooling costs by collecting and storing solar heat. These walls are usually dark-coloured to maximise their ability to collect and hold the sun’s heat, then release it slowly into the living spaces during the early evening.
The results of the study showed that the FSPCM-integrated lightweight wallboard reduced indoor air temperature and energy consumption by up to 0.9–1.5 degC in cool climates and up to 1.2-5.8 degC in hot climates. This reduction in energy usage resulted in heating and cooling cost savings of up to 27% compared to NCP, with a payback period of less than 20 years.