If I make one major energy efficiency improvement to my home, what should it be?
This is one of the most common questions from homeowners because most people who want to make their house more efficient cannot afford to update every aspect of their homes at one time. People want to know what will give them the biggest energy efficiency improvement for the lowest cost. Usually those asking this question have already adopted the easiest and cheapest energy efficiency upgrades, such as changing light bulbs, adjusting thermostats and getting more energy-efficient appliances. But once the easy upgrades are done, what is the next step?
The answer for most homes is to upgrade the roof and attic space. The average US homeowner loses 30 cents of every heating dollar to leaky ducts, house air leaks and faulty or insufficient insulation, according the US Department of Energy.
The roof and attic space are the most important energy features in a home because most heat escapes and enters into the home through it. Homes and buildings are full of small leaks, around windows, doors, vents, pipes and outlets, which constantly work against a home’s HVAC system. The roof and ceilings make up 31 percent of all home energy leaks, the largest contributor in a home. Homeowners can typically save up to 20 percent of heating and cooling costs by air-sealing their homes and adding insulation in attics and floors over crawl spaces.
Unfortunately, there is not one standard rule across the board in terms of which roofing materials and design will achieve the best savings because each home is situated with unique local climatic conditions. These local conditions should tell homeowners which energy-saving techniques to choose from for a roof and attic space, such as thermal mass components, reflective tile pigments and coatings, subventing, radiant barriers, among others. The Oak Ridge National Laboratory offers a detailed map of which type of roofing insulation is appropriate for different climates. They also offer a roof-savings calculator so home and business owners can estimate the potential energy savings.
In colder climates, ceiling and roof insulation is critical for keeping warm air, that naturally travels upward, to remain within the home. This will greatly reduce energy bills and also lengthen the life of a home’s heating system.
In warmer, sunnier climates, the roof should be designed to reflect sunlight instead of absorb it. Over 90 percent of roof tiles in the US are dark-colored, which absorb heat and cause higher energy bills in warmer months. Dark materials also accelerate the deterioration of roofing materials and contribute to the heat island effect when developed areas are significantly warmer than vegetated areas. Instead, roof tiles should be light-colored in sunny places, reducing absorbed heat, reducing cooling costs, alleviating pressure on cooling systems, and increasing the life expectancy of the roof. Simply using reflective coatings on a roof can reflect about 80 percent of the heat. Uncoated roofs typically absorb around 80% of the sunlight.
MIT researchers have even developed a roofing tile that changes color based on the season, absorbing heat in the winter and reflecting it in the summer. New York City, along with other cities, has started to encourage people to use reflective coatings or lighten the color of their roofs to alleviate pressure on the grid.
The color of the roof is important, but also the material choice is critical to home energy performance and its overall sustainability. Many traditional roofing materials are made through toxic processes, deteriorate quickly on roofs, and are not recyclable once they need to be replaced. Investing in longer-lasting materials may be more expensive at first, but will reduce your monthly energy bill and have a longer life. Just like tile color, the best choice for materials depends on local climate conditions.
Although it may cost more to use sustainable materials, it’s only a matter of time before an energy-efficient roof will pay for itself because costs get recovered in various ways:
- The US government provides a 30 percent tax credit for energy efficiency improvements to a home’s roof.
- The value of a home gets raised by $10,000 after roof improvements.
- More durable roof will need fewer repairs.
- In some states, utilities will give customers a financial credit for reflective roofs during air-conditioning season
- There are tax breaks available in some states in addition to the federal tax credit.
- The roof will last three times longer.
- Heating and cooling bills will be reduced every month. Heating and cooling alone costs the average homeowner more than $1,000 a year – nearly half the home’s total energy bill.
With such a major effect on home energy savings, a longer lifetime, and improved durability, a sustainable roof may be the next step to reducing your home’s impact on the planet and your wallet.