Bare minimum thermostat setting?

Vermonter

Is there a minimum recommended thermostat setting to safely leave a home for extended periods without worrying about frozen pipes?

I've been leaving the t-stat at 50 degrees when away for extended periods. Thanks!

Mike T., Swampeast MO

As long as the home is reasonably tight and insulation 45F shouldn't be any problem.

lee_7

i don't like temps below 55 degrees. If something happens to heat, at least at 55, you might have a chance to save pipes. Also not a bad idea to install the weatherwatchman (I think that's what it is called, have not used in a while) that if temp drops to set temp, it can either turn on light for neighbors to see or with some other parts can call you and warn you before pipes freeze.

Alex Giacomuzzi

Depends on How Well You Know Your House....


Just some information to share....

I have also been pondering this same question since the wife and I purchased a home / cabin up in northern Mn. this past summer.
It appears that the rambler house is well constructed for a 50's vintage house of masonry construction with everything finished inside, including the basement. Actually it is very well constructed for its day. The construction in the basement dates back to mid 50's if any of you recall the really thin asphalt cover paper batts that were used back then. It has always been occupied.

I have not done a blower door test on the house, but obviously need to. We have the house occupied, thank goodness and about 3 weeks ago on a Saturday late afternoon, we got a call telling me and my wife the heat was not operational in one of the two upper zones. The temp inside is 63 degrees. The temp outside is quite windy and sub zero --- about minus 15 and still heading down. The house enjoys wonderful solar heat during the day and the living area increases up to 5 degrees above setpoint during the day. This is when the circulator does not run for that zone.

To make a long story short, we drove up to trouble shoot the problem. The house, basement was holding just fine at 63 degrees (set back when we arrived) and the upper zone with the problem was also at 63 degrees. Within a minute I knew I had a frozen pipe SOMEWHERE. I did not know where exactly though. Started turning the heat up in the basement zones and higher in the remaining upper zone. Walked the perimeter to find cold spots. Located some along the front entry which was slate. Set up a small room heater over the area and directed a room fan to blow air in and around the cold area.

Next --- I Sat down and enjoyed a hot cup of coffee..
Checked outside the front door. There was an opening that ran the total length of the threshold. I caulked it closed immediately. I pushed the front door a bit tighter into the door seals.

Temps went down to minus 20 with wind that night and the house warmed up slowly. By 8 am I rechecked the circuit and a slow intermittent drip increased slowly in rate till there was a small stream. No more frozen pipe. Turned the circulator back on and the zone came up to temp.

I truely would have thought the house could have easily have gone down to 45 PREVIOUSLY.. Now I know cold air was getting into the cavity and the pipe was just too close to that entry point. Scary thought --- freezing pipes. We are so happy someone caught it in time. I am still working thru what my next steps to minimize that entry air will be. Finished basements are a bear without supermans vision..

If you know your house well, and you know where your piping is run you are two steps ahead of me...

Just remember --- Mother Nature always wins. Boy was I surprised to find that I had "easy freeze" in my hydronic system. That new product that freezes at 63 F.

Good Luck ... Alex

Gordy

Undetermined amount

As Alex pointed out. A small air leak in the wrong spot when it is sub zero with a driving wind. Will have undesirable results even when a house is at its regular set point. Know your home! the lower the set back the worse it will be if you have a problem area.

How long is extended with what type of heat? Maybe if forced air, drain the plumbing, and no worries. Go as low as you want. If it is hydronic heat, glycol the system. Burst pipes are no treat especially if no one knows for a long time. A little peace of mind goes a long way.

Gordy

Gordy

insulation

Alex, I have some of the thinner insulation in my 50's home with the asphalt vapor barrior, about 2" thick pink? Rock wool??

Seems this was installed in certain areas were stone venier is, but most is 3 1/2" yellow fiberglass unfaced batts... very dense compared to modern day fiberglass batts. Pleasantly surprised wish it were foam but better than nothing.

Alex Giacomuzzi

It looks Like...

Hi Gordy

It looks like rockwool. I did not spend much time examining it though. I also wish I had extruded foam against the walls and some or better sealing at the rim joists.

Have you see or used any suggested foam sealers for the rim joist / top of block area. It appears the floor joists sit right on top open core concrete blocks for the basement walls. There are some areas that I will rework this summer, but the area where the cold appeared has all finished plaster in place.

Cutting off the air flow coming in will be a huge plus..
The reality, is I feel no air currents within the finished space so everything must be moving within the floor joist and rim joist area.

Regards Alex

Gordy

Foam sealers and rim joists

I have a block foundation the top coarse is filled with mortar on mine 12" block. The plate is 2x10 then the joists bear on the plate. They took mortar ran a 45* bead on the inside to dress up the differance in width of the plate, and block.

Have not used the large quanity foam fillers tiger foam ect. They are expensive. I'm cutting and layering EPS in the rim area then sealing with foam in a can to cut down on cost, and mess. Either way rim joist insulation is a large improvement, and a must. I think it will help your problem area sounds like conduction losses.

Gordy

Ragu_5

If you go away....

Have a Low Water Cutoff installed on your boiler, look into boiler antifreeze, look into a multiple alert system (calls over the telephone line in low heat/low oil/locked out burner situations) and shut your well pump off.

If you do get antifreeze installed, definitely have it maintained.

It sounds like a lot of cost, but all of the above are NOTHING compared to the cost of repairing a house when the heating/domestic water systems have frozen, burt and flooded.

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