LESLIE: Dennis in
Dennis, have you tried cleaning?
DENNIS: Yes. Oh, yeah, well, I've been cleaning for a long time. Yeah.
LESLIE: (chuckling) OK.
TOM: He wants to get out of cleaning.
DENNIS: (chuckling) That's right, exactly.
TOM: (overlapping voices) What kind of heating system do you have, Dennis?
DENNIS: We have an oil hot water system.
TOM: It's hot water? OK, so you don't have a duct system throughout the house.
DENNIS: Correct, correct.
TOM: Alright. And any guesses as to where the dust is coming from?
DENNIS: That's the perplexing part. The only vent that we really have that – this is primarily in the bedroom upstairs; I have a split-level home. We have replacement windows in three of the windows between the bathroom and two windows in the bedroom. There is an air conditioner vented outside that's closed up now and – but there's an inordinate – there's always been an inordinate amount of dust in the bedroom and these windows were put in about 14, 15 years ago. And I just can't help but think, for some reason, that they're coming from the windows although ...
TOM: Well, I think the dust is mostly forming from the inside of the house. I hate to tell you this. It's not coming in from the outside.
LESLIE: (overlapping voices) I mean, especially if you've got carpeting or a lot of fibrous – you know, lots of fabrics, lots of ...
DENNIS: For the most part, there are wood floors in most of the house but we do have area rugs.
TOM: Right. Usually, dust forms inside the house. It consists of, you know, debris, dust mites, other substances like that.
LESLIE: (overlapping voices) Skin. Gross.
TOM: Skin flakes, yeah. You really don't want to know; let's just put it that way. (Leslie chuckles) But it doesn't come in from the outside. Now the fact that it's showing up in this bedroom may be related to the fact that you've got this through-the-wall air conditioner; you've got these windows. Because if you've got cold surfaces – remember, as the warm air heats them, it chills, it falls, it creates a convection – sort of a convective loop – that can appear to deposit a lot of dust in one place where it's very visible but in reality it's really throughout the air of the house. And nothing but good cleaning and perhaps some filtration systems are going to help you reduce that.
The reason I asked you if you had a forced-air system – because if you did, I was going to recommend a really good-quality electronic air cleaner. Since you don't have that, your only other option is to go with a portable unit and if it's particularly bad in the bedroom, that might be an appropriate thing to try. But if you do, I want to make sure you get something that's got a very high-efficiency filter rating; like MERV 3 or better.
DENNIS: MERV 3. OK.
LESLIE: And when you say, “Or better,” does the number go up, Tom? How does that work with the MERV ratings?
TOM: Yeah, the higher the number, the more efficient the filter. But typically, you're going to be around three, four, five for a MERV rating on an indoor air filter for a residential home.