January 2, 2021
Dear Ken: We set our thermostat to 67 degrees in the day and 60 at night. Are we saving money? Also, it takes about 1 ½ hours to get it back up to 67 in the morning. Is that too long? Sam
You definitely are saving heating dollars. I like your temperature spread; a six or seven degree setback at night is about right. If you lower the temperature much more than that, it takes too long to reheat everything. Most modern homes lose about that much over a typical winter night—so ideally the furnace won’t run until the thermostat kicks up in the morning.
I’m concerned, though, that it is taking far too long to reheat the house in the morning. At my place, I recover the seven degrees in about 30 minutes or so, depending on the outside temperature.
There are many other factors that can affect your recovery time: the square footage of the house, new or old furnace, duct sizing, insulation, good windows, insulated drapes, and on and on.
Change your furnace filter monthly. Also, locate your return air grilles and make sure they aren’t blocked with furniture. If these fixes don’t help, contact an HVAC contractor, so they can check air flow through your furnace.
If you have one of those fresh air ducts that runs cold outside air into the system, ask the contractor if it can be blocked off. The rules have changed, so we can now draw combustion air from the inside spaces. But DO NOT block up that duct without this consultation, as you risk letting dangerous fumes into the house if you do it wrong.
Finally, many older houses have a heat duct or two run into the garage. That can sap gobs of energy from your heating system. Anyway, they are now a code violation (it was sort of overlooked 50 or 60 years ago) so they should be permanently sealed. Besides the energy waste they, too, can jeopardize your family’s well-being as garage fumes can get sucked inside.
Dear Ken: We are adding exhaust fans as part of our remodeling. Should we run them into the crawl space or attic? Brooke
The attic is the better choice. That’s because the warmish moist air from the fans has a natural tendency to want to rise. And anyway, the last thing your average crawl space needs is more moisture. In the attic space, you’re supposed to run the fan duct outside through a new hole cut in the roof. But for many years, we were allowed to simply point the fan duct directly towards an outside gable or roof vent, without having to cut a new hole to the outside. It seemed to work just fine; I’ll leave the choice up to you.
And don’t forget to create a flat spot in the duct by curving it level for a foot or so. That will create a water ”trap” that will prevent condensed moisture from running back on to the sheetrock around the ceiling fan.
Dear Ken: We had some loose tiles. I removed them and found moldy drywall. There are studs and insulation behind the wall. How far should I invade to fix this? Sheila
You should keep going. Like a dentist filling a cavity, you need to go deeper and wider until you’ve seen all the damage and reach pristine drywall. Then, remove the moldy insulation and sheetrock, and seal it in plastic bags for disposal. If the 2” x 4” studs are rotting (a pocket knife penetrates them easily), they will have to replaced.
Once you’ve dried out the wall cavity, wipe it down with some Clorox and water to kill mold spores. After it’s dry apply two or three coats of KILZ or Bullseye 1-2-3 primer sealer. You could use waterproof (green) sheetrock as a replacement, but I prefer the cement-based backer sheathing, like Hardie Board.
Your question is a very timely reminder to the rest of us about maintenance in the bathroom. Even tiny pinholes in and around the tile in tub and shower enclosures can, over time, really cause inordinate damage--as you are finding out. That’s why it’s important to re-grout ceramic tile whenever you start to see chunks slough off during normal use. Also, renew the edges of the tile itself (corners and at the tub or shower base) with a good tub and tile sealant. I like the DAP siliconized product, but whichever you choose, do it often—say two or three times a year.
Dear Ken: My house is over 90 years old. The furnace and water heater vent through the old brick chimney. Recently, I’ve noticed paint peeling on the ceiling around the chimney. There is also some black gunk. What’s going on? Caleb
It may be melting snow leaking around the tarred flashing at the base of the chimney, or it may be combustion products oozing through the old brick and mortar. Rub some of the black stuff on a finger and smell it. It will either remind you of tar—like you smell when they are repaving the street—or it will have a burnt scent. I’ll bet it’s the latter, and that means that the chimney is letting condensation products from the furnace and water heater flue gases back inside the attic and then on to your ceiling.
It’s been a requirement for some time that these old chimneys be lined with an aluminum duct, so the fumes go directly up and out, without oozing sideways into the house. That can let carbon monoxide build up in the attic—a really hazardous situation for you and your family. Bottom line: Call an HVAC contractor right away to check it out. I’ll bet they recommend a chimney liner.
