- What is the most efficient way to bring combustion air from the exterior?
- Can/should heat recovery ventilators be used to bring in exterior combustion air?
I am converting an old church building to a two family residence. The building has a small boiler room in the basement which has no intake of exterior air, except what comes through the interior. For the conversion, I need to fire separate the boiler room, and based on this volume, there is not enough interior combustion air to meet code; my code officer requests that I pull exterior combustion air.
The most straightforward solution is to send the code required ducts to the exterior, which are fairly large as the total BTUH are in the 650k range. Another option is to use an expensive forced ventilator. I am wary of EITHER of these cases, as they would bring in cold exterior air to the boiler room; it seems that some of the heat from the boilers would be lost to this colder air temp - isn't this the case?
Another possible option: I've seen many different types of heat recovery ventilators (HRV). These are typically used to Exhaust stale air, but can you use these as combustion air intakes if you just exhaust both the "stale" and heated fresh air into the boiler room (rather than exhausting the "stale" air to the exterior). Based on the energy consumption of the HRV, would it even be worthwhile in this application?
I'm looking for any ideas or perspective on the situation.