Helpful? 0

ERV ?

We are renovating a 12 (one bedroom) unit elderly complex with a direct vent hot domestic hot water system and electric heat. The units are 530 SF. Our work includes adding 3" of rigid insulation to the exterior, adding an additional 12" of insulation to the attic space and going after air infiltration discovered in a blower door test. We are thinking of adding a small 40 CFM ERV to the system but are worried about dryness and effectiveness of energy savings.

Thank You

Asked by Michael Lassel
Posted Wed, 01/23/2013 - 11:02

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3 Answers

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1.
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Michael,
You didn't mention your climate.

What do you mean when you write that you are "worried about dryness"?

If you are adding exterior rigid foam and tightening up the building, you need to include a mechanical ventilation system. You can either install 12 small ventilation systems (one per apartment), or you can install a single ventilation system for the entire building.

More information here:

Designing a Good Ventilation System

HRV or ERV?

Answered by Martin Holladay, GBA Advisor
Posted Wed, 01/23/2013 - 12:06

2.
Helpful? 0

Martin, sorry, the location is Coastal Southern Maine. Agree with the need for make up air. Thank you for information. Are there any systems you might recommend?

Answered by Michael Lassel
Posted Wed, 01/23/2013 - 14:13

3.
Helpful? 0

Michael,
I think that 12 small ventilation systems will work better than a single system serving the whole building.

You might consider using the bath exhaust fans to provide exhaust-only ventilation; The Panasonic Whisper Green fan can provide continuous low level ventilation, as well as more powerful exhaust when needed.

If you don't want exhaust-only systems, but prefer an ERV, the Panasonic WhisperComfort ERV might make sense for these small apartments.

Answered by Martin Holladay, GBA Advisor
Posted Wed, 01/23/2013 - 14:24

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