DIY home energy audit: HERS Index Score, Audit Checklist
- 26 Oct 2021
- 13 min
In a typical house, more than half of the energy goes to heating and cooling it. Lots of energy is lost in the process. The reasons can be different: bad insulation, ventilation problems, old electronics. The outcome is the same: you constantly overpay for electricity. What you need is to do a DIY home energy audit – a full energy check-up of your house.
Home Energy Audit shows how the house uses its resources
The word ‘audit’ may sound complicated, but the idea is actually pretty simple – you just want to figure out how your home uses the energy it gets. There are quite a few things to check: the insulation, the heating, the chimney, if you have one, your appliances and lighting. Finding spots in your house where you lose more energy than you should allow you to decrease your electric bill.
Devise an Energy Audit Checklist
In the beginning your house may suddenly seem like an uncharted territory. Start out with a plan and prepare necessary tools. The list of equipment that will help you along the way includes:
- Wattmeter to help you measure the power your appliances draw.
- Caulk, weatherstrips, spray foam for fixing holes and cracks.
- Infrared camera to show the insulation state of your house and the spots where heat escapes. A helpful tool, but don’t stress, if you don’t have one.
- Pen and a printed energy audit checklist.
Locate air leaks
Air leaks are a huge problem in the winter and the main reason why it’s so cold in the house even though you spent a ton on central heating. The leaks by themselves can lower the heating efficiency by 30% or more. Finding them and insulating your home in every possible way is going to be the primary concern of an energy audit.
The most likely place where leaks are located are widows. You have to check them from inside and outside as well, if possible. The easiest way to detect leaks can be using your hand — try to find small streams of cool air along the perimeter of a window. Another smart method to locate them would be to light up an incense stick and watch for smoke behavior. If it strays, there is a leak. However, the best possible tool for this task is an infrared camera. Once you’ve found the leak, use some caulk and weatherstrip seals to insulate the window.
Here are the places you need to check apart from windows:
your annual bill for each window you insulate
- Doors. Use weatherstrip seals. When examining doors, don’t forget the bottom and the threshold – it should be installed or replaced if you detect a leak.
- Outlets and switch plates. Basically, those are just holes in your walls. Foam or rubber gaskets will seal them off.
- Places where the wires and pipes come into your house. Spray foam is the go-to choice here.
- Joints between floor and walls, ceiling and walls. Here caulk or spray foam work best.
- The basement and the attic are considered especially problematic, being places with lots of holes and cracks. It’s reasonable to seal off the attic and basement hatches completely. Be careful not to block the vents with insulation. Caulk is good for small holes and foam is good altogether.
Air conditioning system is one of the most energy-demanding units in the house. To minimize its electricity consumption, it makes sense to change air filters regularly – even as often as every month. The cleaner your air conditioning is, the less energy it needs to work steadily. The insulation in your house obviously should not block the ventilation.
AC units also get old and, as the time goes by, they start to consume more energy and even add unwanted gases and dust into the air. When you see that your air conditioning degrades, think about replacing it. Electric companies often offer rebates for the installation of a new AC unit – check for available programs with your utility. If you think that your AC unit eats too much energy, you can replace it with a ceiling fan.
Break down your electricity bill
Most of the time your electricity bill isn’t detailed and you don’t know exactly how much power you spend on what. Modern control panels keep count of your energy consumption and provide you with all the necessary data on how much power was spent on heating, refrigerating or went to appliances. If you have a solar system with an inverter, modern models usually keep track of the energy consumption in the house. Overall, just knowing where your energy goes gives you the targets for future efficiency improvements.
Review your home lighting
Lighting generally makes 9-10% of your bill, so there is no reason to overlook it. Incandescent light bulbs are obsolete – if you use those, they become quite a burden on your electric bill over the year. The best option is to replace them with LED bulbs. They draw much less electricity and last for years and years.
Take a look at your appliances...
Up to 10%
of your bill is made out of ‘phantom appliances’ consumption
The simplest way to calculate your appliances’ energy consumption would be to measure the power of every gadget with a wattmeter in the house and multiply it by the number of hours in use. However, appliances tend to draw electricity little by little even when in standby mode. These ‘phantom appliances’ may account for 10% of your bill. Unplugging them every time is a little tedious though. What you can do is to order some smart outlets that don’t let appliances suck out the energy that they don’t need. Using power strips that you can turn on and off is also a good option.
...and consider upgrades
If you are ready to go big on upgrades, consider replacing old appliances with new ones. Look for Energy Star labels to make sure you are buying the most green and efficient products. By using Energy Star labeled appliances an average household can save around $450 on their energy bills. Solar panels are also considered an efficiency upgrade. They can cover all your electricity needs and even bring in money through the Net Metering program. While all these upgrades can be costly, they pay for themselves in time.
Check the water heater
The standard temperature for a boiler is 140 °F. However, the Environmental Protection Agency (EPA) recommends turning it down to 120 °F – this will save you energy and money. While you are at it, check the insulation of the water heater. 10 years ago companies used fiberglass insulation which isn’t the best option today. Touch the heater – it shouldn’t be warm. If the insulation is old, replace it with an insulation foam blanket with a minimum rating of R-8. You can add foam sleeves on pipes to help them preserve heat. As a result, you can lower the costs of water heating by 8-10%.
Purchase a programmable thermostat
Since so much of your energy goes to heating, it makes sense to take control of that process. To do it, you can purchase a programmable thermostat. Here is an example: if you go to work in the morning and come back in the evening, you can set the thermostat to lower the heating of the house during the daytime and turn it back up later in the day. A programmable thermostat usually pays for itself in a year or two. You can also find smart thermostats on the market which decide by themselves when it’s better to heat up the house or let it cool down.
Examine the fridge
Fridges never get a day off, and the work without holidays eventually exhaust them and make them less efficient. Check how tightly its door shuts. Put a piece of paper between the fridge and its door, close it and pull the paper out. If it slips out without any resistance, the fridge spends a lot of energy in vain daily. If your fridge has served you since the 90s, then it’s wiser to buy a new model, because old fridges draw a lot more energy than new ones do. Of course, the location matters: the fridge should not be standing next to furnaces, ovens, or in plain sunlight. Remember that the fridge maintains the temperature inside better when it is full.
Electrical engineer and blogger at MyIntelligentHouse
Don't overdo the upgrades though. Sometimes, in our eagerness to rescue the world (and save some money), we could wind up shelling out a fortune for improvements that take a very long time to pay off. Be wise and prioritize high-ROI changes first. Focus on proper insulation of your home and an energy-efficient HVAC system — it’s where the efforts always pay off.
Consider a professional Home Energy Audit
While there is usually a lot to do without any sophisticated gadgets, you can get even better results by ordering a professional audit. Its cost can go up to $500 and it takes about 4-8 hours, depending on the size of your house. What is more, certified experts can evaluate your HERS rating, which will help you later if you decide to sell your house. If you decide to go for a professional audit, here’s how to pick a company for it:
- Before signing a contract with an energy assessment company, get a few references and ask if they are satisfied with results.
- You can also call the Better Business Bureau to check for complaints.
- Ask the company what kind of equipment they use. What you definitely want them to have is a calibrated blower door and infrared camera for thermographic inspections.
- Ask if the company provides HERS score.
Before the arrival of contractors, prepare the following in advance:
- List of possible problems and concerns to discuss with the auditor;
- Copies of electric bills.
HERS Index Score shows how energy-efficient your house is
Lower HERS score increases you house resale price by 3-5%
HERS stands for Home Energy Rating System which shows the energy-efficiency of a house. Houses are rated based on the 0-150 scale: the lower the score, the more energy-efficient the house is. Typical resale house is somewhere at 130 points and a new one scores around 100. The rating contributes to evaluating the price of your house on the property market if you decide to sell it.
You might also inquire about HERS rating of a house before buying it and draw conclusions about anticipated bills and costs. Houses with a low HERS score tend to be 3-5% more expensive than the ones with higher HERS numbers. Besides, HERS ranked homes are sold 2.7% more often than unranked ones, and their buyers have better mortgage profiles. Certified HERS raters are all included in the National Registry and you can find one in your state using this service.
Look for rebate programs in your state
The utility companies that provide you with energy also want their customers to use their resources in the most efficient way. That is why some electric companies offer rebates on energy-efficient upgrades. For example, in Arizona the Southwest Gas Corporation gives a $500 rebate to builders for a home with a HERS rating of 60 or less. Tucson Electric Power (TEP) provides up to $900 in rebates for adding upgrades, like Energy Star AC or duct sealing. Some companies may even perform an audit for free.
Making 100% efficient house isn’t the goal
The bigger your house, the longer and more complicated your home energy audit. Accept the fact that some issues you probably will not be able to address. Making a 100% energy efficient house shouldn’t be the goal, and certain problems can be solved only by professionals with special equipment. However, improving and optimizing the use of energy in your own home will not only reduce your electric bill by the end of the year, but will also make you a more responsible homeowner.
If you want to learn more about designing an eco-friendly house, we suggest checking out an article about sustainable architecture by Redfin. There are lots of tips from experts in different fields on saving money with energy-efficient upgrades and making your home a healthier place to live.
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