• Welcome to the new and improved Building Code Forum. We appreciate you being here and hope that you are getting the information that you need concerning all codes of the building trades. This is a free forum to the public due to the generosity of the Sawhorses, Corporate Supporters and Supporters who have upgraded their accounts. If you would like to have improved access to the forum please upgrade to Sawhorse by first logging in then clicking here: Upgrades

Heat Pump Discharge Air

John shane

Registered User
Joined
Feb 13, 2020
Messages
9
Location
California
Hi Everyone,

So we are redesigning an existing residential apt and we are providing a heat pump water heater because the house doesn't have gas and more so we can't pass t24 with an electric water heater.

We all know that environmental air exhausts termination need to be 3ft away from openings into the building. Now, is a heat pump's discharge air considered as an environmental exhaust and would need to follow that termination clearance too? As far as I know some installations even install discharge of a heat pump with 2 way ducts so that in summer you can use a damper and direct the cold air for additional cooling to the house.

The only place that we could duct it is to a wall is in between 2 windows, the wall length is just 3 feet so we won't be able to comply with the requirement.

Honestly I just think that I can do it as it is clean air that is being discharged to the environment. Wdy guys think
 

cda

Sawhorse 123
Joined
Oct 19, 2009
Messages
20,358
Location
Basement
Not my area

Interesting did not know they made a

heat pump water heater

I vote for three feet required


[MP] MECHANICAL EXHAUST SYSTEM. A system for removing air from a room or space by mechanical means
 

mtlogcabin

Sawhorse
Joined
Oct 17, 2009
Messages
7,979
Location
Big Sky Country
What does the manufactures installation instructions say? Do they require the air to discharge to the outside?
You are not removing products of combustion or environmental air
 

Paul Sweet

Sawhorse
Joined
Oct 17, 2009
Messages
1,646
Location
Richmond, VA
Is the heat pump a split system? Most of the heat pump water heaters I've seen have the heat pump built on top of the water heater and just recirculate air. I think they require a certain minimum volume of the room they are in to minimize short-cycling of the air.
 

classicT

Sawhorse
Joined
Aug 2, 2017
Messages
1,816
Location
Washington State
Is the heat pump a split system? Most of the heat pump water heaters I've seen have the heat pump built on top of the water heater and just recirculate air. I think they require a certain minimum volume of the room they are in to minimize short-cycling of the air.
That's all that I have seen.

The one side note that I have with these heat pump water heaters is that they pump out a ton of cool air. For that reason, they are best installed in a dedicated mechanical room or garage. If installed in the home, they will scavenge the heat from the home, and pump out the cool air. If in a laundry room or similar, it can make the area feel like it has quite a draft.
 

mark handler

Sawhorse
Joined
Oct 25, 2009
Messages
11,058
Location
So. CA
First thing to look at is the manufacturers Installation Clearances. Also how much Clearance is required for Maintenance and Are there Zoning restrictions on placement?
 
Top