Does HRV/ERV system reduce your electricity cost?
bennagio
| Posted in Energy Efficiency and Durability on
Hi,
I live in Thailand which is a tropical region. Temperature can get to 100F in summer
I am in interested in installing HRV system in my house. Some people say installing HRV system can reduce electricity cost due to less air conditioning power needed.
Please share if you pay more or less for electric bill after installing HRV system.
Thank you very much
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Replies
Of course you pay more. Your operating one more fan motor.
Chanpakong,
In addition to the cost of the electricity to operate the HRV fans, you will also have higher air conditioning costs. When you introduce outside air into your house, the air has to be conditioned -- in your case, cooled.
The more you operate the HRV, the higher your air-conditioning bills will be.
An option that could make sense would be an ERV rather than an HRV. Given your tropical location, it is likely that removing humidity costs more than cooling outside air. With an HRV, the outside air that is brought in is cooled to near the inside temperature, but it still needs to be dehumidified. With an ERV, the outside air that is brought in is dehumidified some, and cooled some. It still takes more electricity to finish the job, but not much more.
Why, then, would anyone install an ERV, if the amount of electricity needed goes up? It only makes sense if you also seal all the other air leaks in the building envelope. If you just seal the leaks, you might not get enough fresh air inside. If you seal the leaks and run the ERV, you get fresh air again, and the energy needed to condition a given amount of air coming in through the ERV will be less than the energy needed to condition the air coming in the leaks.