Yet another condensation question

You run a dehumidifier in the basement and a humidifier on the furnace. With condensation on the glass your humidity is to high turn down the humidifier till it stops , or turn it off.

You may need several kinds of expertise. Heat Gain / Loss and Duct Sizing by a competent HVAC tech or Mechanical Engineer. This would investigate the furnace size and perhaps help with window condensation & moisture problems. (It's not clear to me whether all or only some particular windows have condensation problems. A tech rep from a paint company might address the paint problem, at least in part.

Forensic architect or engineer specializing in building envelope, rather than - say - structural, problems might address venting and basement problems.

TB

It sounds like many small (some may be expensive) problems. I suggest you may want to start with a home inspector. These are the guys you usually hire when you buy a home. They can go over you home check out all those things you listed, maybe find a few others and help you decide which ones need fast attention which should be done and which you can live with. It would really be difficult from here to do the job right.

Just a couple of comments about what I did read or guess.

That bath vent should NEVER be venting in the attic it should always go outside. That is not causing any of your listed problems, but it can cause others.

Vapor barriers never go under the siding they go under the drywall in cool zones. Tropical zones are different.

The mold growth means too much moisture. Maybe someone needs to run those fans more often or you need larger fans.

You have done a lot of good thing. You are moving in the right directions.

If I were to guess, I would say you may be lacking a vapor barrier. That and addressing the basement moisture (does the ground slop away from the house in all directions?) should help a lot. You may need to reduce the humidifying during the winter until you get better windows. Generally you want to set the humidifier to just under the point when you get moisture on the windows. Opening drapes and curtains etc from the windows will reduce any condensation.

I must, for the first time, disagree with Mr. Meehan - or at least add a note of caution. I do not think a home inspector is the best choice for analyzing the problems. In my experience, they do visual inspection and no calculation. Some of the existing conditions suggest to me a need for deeper investigation. TB

You are certainly partly right and partly wrong as was my advice as far as it went.

The problem is there are good home inspectors and ... well to be kind some not so good.

A good one would be a good choice as there are a lot of issues going on and I would want someone who did not have a vested interest in the outcomes do the inspection. Any contractor would have a vested interest, and while most are honest, that conflict is just one thing that can be eliminated by a home inspector.

I did consider, but failed to provide any acknowledge of this in my original message. I thought I had been wordy enough.

You are right that most home inspectors will not be as knowledgeable in any one area to be able to define all the specific correction steps needed, but I would hope that any good inspector would identify the problem areas leaving the specifics of the correction to the more knowledgeable specific contractor.

Do you think the house builders tried to make the house airtight? This became a problem in Ontario, Canada, about 30 years ago, solved by requiring (in building code) exterior air supply to (non-electric) furnaces. The cheapest solution was to pierce a hole through the basement wall nearest the furnace (covered by a trunk hanging down, three or four feet long.) Exterior air is much drier than indoor air in Canadian winters, so the furnace should use the drier air.

I really don't see any issues that may not be normal or your effect on the house. Windows condensing and especially with storms on is no more than excessive humidity you are adding by your humidifier. Your basement Dehumidifier and humidifier are fighting each other. Solution , turn down or off the humidifier till condensation stops or mold and rot will occur. This is the way humidity is set as an accepted rule that works.

Your paint issue could be directly related to over wet wood expanding outward in suns heat popping paint, This is also common of trapped moisture in wood. , Solution again, lower your humidifier till No condensation occurs as it builds on the glass it then runs onto , into the wood and does not dry out for months in summer. Eventually you will just rot your windows if it hasn't already started. What primer and paint are you using, Many newer primers are just not up to all jobs, for windows a regular oil slow drying primer is the only thing most pros use and is the best even recommended by the best paint companies like Ben Moore, Sherwin williams. Paint should be the best Latex that actually allows moisture to release.

You need a humidistat in several areas. Not the cheap analog Taylor, which I have never purchased one that is even 10% close to actual humidity but better a digital, Or a large Taylor that comes with calibration instruction, and even Taylor recommends calibrating every year.

You are not clear on the bath vent, is it on the soffit going outside, this is ok, just so long as it is not in the attic.

Yes mold will grow in the right conditions, your humidifier setting is giving it what it needs. Spray the mold with bleach, it will kill it.

Your furnace may be oversized or just set to cycle to often, which is hard on the equipment and its efficiency, is there a temp swing in your house or does it stay even. Do you heat the basement-circulate the air. If it is oversized the dryer upstairs air will dry out a basement in winter, and give longer cycles . You may not need a humidifier or dehumidifier at all and both running at the same time with simple air movement to the basement, Are there returns and supply in the basement.

Your bath fan may be ineffective in Cu ft of air pulled out. and can`t dry the bath I really don't see any issues that are serious except maybe the bath vent, it seems you are causing problems with the humidifier .

Jerry,

The siding itself acts as a vapor barrier. You have not said if the is primarily in the winter or summer or all year? Is the window sweating on the inside or outside? The bath exhaust should vent outside, not in the attic. Some of your problems could be caused by improperly vented fuel burning appliances, that could cause carbon monoxide problems as well - do you often get headaches? Depending on your climate, exhaust fans could make more problems than they cure. When exhaust fans run they blow indoor air outside. That puts the house under a negative pressure which draws outside air back in. If there is moisture in the outside air, it may hit the dew point somewhere inside the wall, causing condensation and then mold. A blower door test would be advisable. A home inspector may or may not know how to do this. Where are you located? Some problems are location specific.

Stretch

Thanks to all who replied, I'll try to address your comments and fill in the blanks I left.

The house is in central Connecticut. It is on the North slope of a hill. When we moved in, much of the house (including some of the windows that wouldn't hold paint) was in perpetual shade; the neighbors' yards were full of pine trees much taller than our houses, and there were trees and overgrown shrubs up against the house. We've all done significant cleanup since then, so the house gets more sunlight now. There is actually algae growth on some of the siding where the sun never shines, even now.

I suspect that there is an underground water flow down the rock ledge that forms the slope: our back yard tends to stay squishy, despite being on a hillside, until midsummer. The yard slopes past the house.

I have no idea what is under the siding. When they built the house, they probably did try to button it up tight; at least, I'm guessing that's why the attic had almost no venting. There was blown-in insulation in the attic, whether they tried to stuff it into the walls or not I don't know. I added two layers of blanket insulation when we shingled the roof and added all of the attic vents.

I realize that running a humidifier and a dehumidifier at the same time sounds silly, but the basement is so much more damp than the rest of the house that it seems necessary. Even with the furnace-based humidifier going, you can still get a decent spark walking across the carpet in winter. Our hygrometers are digital; they may or may not be accurate, but the one in the basement generally reads 35%-40% and the one upstairs generally reads more like 25% in cold weather. Remember that the humidifier only runs when the heat does, so what it really does is mitigate the dryness of the hot air coming from the furnace.

Speaking of the furnace, the house temperature doesn't fluctuate much in the room where the thermostat is. Obviously a house this big and with this floor plan would be better off with multiple zones. There is no real return in the basement (other than the access door of the furnace), but there is an outlet that is left open in heating season.

We don't have any carbon monoxide problems. The furnace and hot water heater vent up a chimney.

The laundry appliances are in the kitchen, which has never had a visible condensation problem; it is one of the few spots on the ground floor that gets any sunlight, so that might be why. We replaced the kitchen window not long ago for looks, but it was in pretty good shape so far as I recall.

The dryer vents directly to the outside; so does the fan in the downstairs lavatory, but it gets used rarely and I don't see any signs of moisture in that lavatory. Whoever installed the fan in the windowless upstairs bathroom was a moron; originally, the fan simply vented directly into the attic. I added the fan in the master bath (which has a window), and ran the exhaust to as close to the vented soffits as I could get. I'm not personally skilled enough to put in a roof vent; that would be an obvious step the next time we have work done, but at the time I figured running them out into the eaves was a heck of a lot better than letting the moisture accumulate in the insulation.

The master bath, and adjoining bedroom, are really the only rooms where there is noticeable moisture on the inside of the windows. The other windows with obvious problems are the ground floor casements, which are shaded (North side of the house, and shaded by the neighbor's pines). Their construction is part of the problem: they are single glazed with a removable second pane (inside). This was obviously an attempt to make them their own storm windows, but since the inner panes aren't sealed you get moisture condensing between the two panes. That may be the bulk of the problem.

The basement is damp in the summer and (to a lesser degree) in the winter. The condensation problem I'm talking about is a winter problem.

The master bath is a problem, period, because that's where my wife and I take showers in the morning. Since the heat goes off for the day shortly afterwards, I rely on the exhaust fan to clear it out; but an hour later, there's still sweat on the toilet tank (even if I leave the fan running). The fan does move some air, but perhaps just not enough.

The first floor casement windows are probably a victim of their construction, and nothing will do for them but replacing them with properly double-glazed ones. That, and fixing the bathroom fans to exhaust to the outside (and maybe putting in a larger one), would probably take care of the bulk of the problems.

The more I try to explain this, the more I suspect that we might have already mitigated much of the problem. I'd like to find someone who can take an objective look at the situation, so I don't put in new windows only to have them rot away.

I just hope that when the siding is eventually replaced, they find intact studs not rot.

It seems the bath needs a better fan, and proper ducting that could cause the adjoining bedroom wall mold, Panasonic has very good quiet fans. I use a timer switch to keep mine running You could easily cut in a return in the basement that will circulate air and dry it out better and bring moister air upstairs, If you have not had a lack of heat issue and it is cool another closeable supply would help.

The windows that have the added interior storms you might try thin foam weather stripping to make an airtight seal, Shop, there are all widths and thicknesses available and it is cheap, The thinest may be the best so it compresses and you can get the storm back on. If these windows are peeling, moisture sounds logical as it is trapped and is going into the wood. Even without sun I have the same issue on old windows with add on storms inside. If interior wood is Latex paint on windows this will not help as latex allows moisture to penetrate in to wood. Oil would be better.

You might try leaving the blower on for better circulation, it may make the humidifier add more moisture depending on the unit and its controls. Your thermostat should have a setting to increase swing so you get longer cycles and less wear on the unit. It should be an anticipator or an adjustment for temp swing. 25% is low It realy doesnt sound like to much to fix up except for your wet yard . If it is soggy a drain tile system, [ plastic pipe] directing the water away is worth a consideration, perhaps grading also.

I have to agree with everything above.

Jerry,

The toilet tank sweats because the cold water that fills it is below the dew point of the air in the bathroom. When I was a kid growing up in Pennsylvania, my father added an adjustable device to mix hot and cold water going to the toilet. This way the toilet filled with warm water in the winter and did not sweat. The windows sweat because the surface of the windows are below the room dew points. Normally in cold climates, you want to keep the RH around 35%. At 75 degrees room temperature and 35% RH, the dew point is about 46 degrees. Any surface in the room below 35 degrees will sweat. You must either raise the surface temperature (Better windows or warmer water in the toilet) or lower the %RH. Get your HVAC contractor to look it up on a psychrometric chart for you. He should ahve that chart.

Stretch.

If his toilet is sweating and mold growing a good bath fan running longer and turning the forced air fan to ON , to circulate out the humid air should do alot, running just my furnace fan will noticably raise the rest of the houses humidity and dry out the bathroom quickly after a shower. He has humidity in the house, just it is where he doesn`t need or want it , the bath and basement. Putting the fan to ON for a good period of the day will probably help alot of his issues and reduce dehumidifier and humidifier needs.

Good suggestions from everyone, I just have to decide what makes sense economically.

Leaving the furnace fan on constantly would certainly level out the temperature and humidity in the house, but I'm afraid of what my electricity bill would look like. The thermostat is a fancy one that heuristically determines what to do, but I'll check to see if there's a setting to increase the swing.

As it happens, I was outside today and realized that those windows that are in the worst shape are on sides of the house where there is a lot of exterior staining from algae and mold. That goes along with the squishy yard and the shade; some of the staining might be old, before some of the trees were removed. Grading won't help, I think, since the yard has a significant slope from the very back down to the street. There's no ponding, except in ruts caused by the lawnmower. My next door neighbor just went through an extensive project to drain water away from his basement, and the major result of that was a dwindling wallet.

It never occurred to me to weather-strip those removable glass panes in the casement windows. It would have been a good idea, but I fear the damage may be irreparable after 30 years. I don't know if those "turns rotten wood into a hard, paintable surface" products (naval jelly for wood?) work. The exterior paint that jumped off these windows was oil. The interior wood was stained and varnished at the factory, so fixing that up (I think) would be like refinishing furniture; new windows would probably be cheaper.

It sounds like a bigger bathroom fan, with a better vent, would be the easiest thing to implement. When I first installed it, I wanted to put it on a humidistat; but my wife didn't want the thing going on and off while we were sleeping. I'm considering a new furnace anyways, what with the jump in gas prices, and that won't hurt.

If I had my druthers, the house would be made of stainless steel.

A furnace blower for my old 110000 btu took 375 watts, your dehumidifier could pull 5-800watts, a guess. Its not that much at 12hrs extra running the blower it would cost me at .12kwh 18$ a month.