UV Light in a heat pump

Bigriver

I am working within the confines of a grant to replace a heating system. The grant needs to show that the new system will improve building air quality. Can UV lights be installed in heat pumps and is there one you would recommend? Thanks!

STEVEusaPA

You mean in the duct work? The person/company replacing the heating system could inspect your system and recommend the proper components.

EdTheHeaterMan

UV lamps can be installed in almost any HVAC duct system. Selecting the best location has a lot to do with where Mold might grow. In line of sight to the (cooling season) evaporator coil. This is where there is the most moisture and it is dark and the temperature is the best for growing micro-organisms. A Pleated filter or EAC can be placed in the return duct just before the air handler return opening. Just don't use a pleated filter that over restricts the air flow with heat pumps. The less expensive pleated filters are less restrictive. If you use an electronic air cleaner (EAC) then you can eliminate the restriction of an air filter. Proper maintenance of the EAC collector plates is needed or you may as well not use a filter at all.

Jamie Hall

As noted, UV lights can certainly be installed. Where they are installed depends on what you want them to do. Destroy airborne pathogens? Reduce or eliminate mold on the coils? Two very different applications. And keep in mind that those are the only two things they will affect. They won't attack most odours. They won't attack harmful fumes. They won't attack particulates. They won't change humidity. Etc.

So yes, they can be installed. You would need to define what it was you wanted them to do, and then contact the manufacturer or representative for sizing and installation guidelines to accomplish that, and then include a statement from the manufacturer that they will do what they say they will -- and that in fact that hat is a problem with your air which needs to be improved.

pecmsg

I don’t see how a UV light will “improve indoor air quality”?

mattmia2

How do the plastic parts of a coil fare being exposed to strong UV, especially the drain pan?

JakeCK

I'm probably wrong here but I've always felt UV lights in an HVAC system are kind of a gimmick. Seems to me for UV radiation to actually damage enough of the DNA of pathogens as they pass by the bulb it would have to be extremely powerful and energy hungry. I'd rather trust a massive HEPA filter that both removes particulates and most pathogens over UV bulbs. Both need to be replaced so often too.

I can see the utility of it being around the evap coils but seasonal PM could accomplish much the same for mold control, and that cleaning will have to be done periodically anyways.

Jamie Hall

Well, both @pecmsg and @JakeCK are completely right. UV light, unless it is very powerful, won't kill much of anything, and most indoor air quality issues are either better managed by good filters or air exchange with outside. In short, it is a gimmick. However, our @Bigriver , our OP, is working with a grant here, and if he can get enough money from the grant to cover the cost of installation, more power to him. Grants are not known for intelligence nor engineering smarts; you do what you have to do. I don't think it will actually hurt anything.

JakeCK

He said he only needs to show it will improve air quality. An hrv or erv combined with a good HEPA filter will absolutely improve indoor air quality, infinitely more than a uv light bulb that no one will ever remember to replace... Unless the building already has that installed correctly I don't see why that wouldn't fit the criteria?

Bigriver

Thanks all for your thoughts. Grants are great for the $, but can be very annoying. Can a uv light be installed in a ductless heat pump? I am not as familiar with an HRV, would that do the trick in showing that air quality is improved?

GGross

@Bigriver

We have installed UV lights into some indoor mini split heads in the past. There are several companies that make these specifically for ductless splits. I think this is one we used in the past

https://www.freshaireuv.com/residential/mini-uv-led/

ChrisJ

I had considered a UV light to keep nasty stuff from growing on the evaporator.
The issue I had was, as others had mentioned it seemed like the ones sold for residential HVAC are too weak to actually matter.

It also seemed like I'd need at least 3 of them for just the A coil. So I forgot about it and moved on.

Bigriver

Thanks @GGross and @ChrisJ