electric floor heat question

[bigbrad123]

My floor heat in the garage is controlled by a regular digital wall thermostat.


So you don't have an in-floor sensor probe? Your's just detects air temp?

Looking at whether something like this may be better for my system:

https://www.azelcontrols.com/store/product.php?productid=16166

 

[Hookin8easy]

Typically yes it is a wall mounted stat not floor temp, it's probably a good idea to change out the stat if it is a mercury style yet- not very accurate but that may not be an issue either

 

[pluckem]

Suggestions what to look for? I do need to check out insulation in the walls. At times, it seemed like our bedroom walls on the northwest side was kind of cold, but I figured that may be kind of typical when the wind blows. It's a bi-level. What do I need to check out in the floor? It's a completely finished basement. I've started to wonder if the whole unit isn't operating properly. It works, but I'm not sure how much it is cycling on and off. QUOTE]

I really don't have much real world experience in it, besides the fundamentals.

You just want to make sure your slab (that has the pex running through) it is isolated/insulated from all other heat sinks which would be the soil or other slab underneath and the foundation walls. You want to make sure the only direction the heat you input into the slab can go is up and into the living space. If you don't have the right insulation in the right places you are just paying to heat the soil around your foundation walls and under your slab.

I would see if you can find out who installed it and get details from them. Hopefully the builder didn't cheap out on the insulation.

 

[bigbrad123]

Suggestions what to look for? I do need to check out insulation in the walls. At times, it seemed like our bedroom walls on the northwest side was kind of cold, but I figured that may be kind of typical when the wind blows. It's a bi-level. What do I need to check out in the floor? It's a completely finished basement. I've started to wonder if the whole unit isn't operating properly. It works, but I'm not sure how much it is cycling on and off. QUOTE]

I really don't have much real world experience in it, besides the fundamentals.

You just want to make sure your slab (that has the pex running through) it is isolated/insulated from all other heat sinks which would be the soil or other slab underneath and the foundation walls. You want to make sure the only direction the heat you input into the slab can go is up and into the living space. If you don't have the right insulation in the right places you are just paying to heat the soil around your foundation walls and under your slab.

I would see if you can find out who installed it and get details from them. Hopefully the builder didn't cheap out on the insulation.

No idea who installed it Pluckem. It's my understanding I'm about the 3rd or 4th owner of the house. I could try to dig around in the records I got from the others, but you know how that goes. Odds are probably slim I could find out. So, I don't know anything about how the foundation was insulated during installation of this system. I guess at this point I am looking into the following:

1. Would putting a floor sensor and a new thermostat help (detecting temp of the floor/slab vs. temp of the air)?
2. How well are my basement walls insulated (may have to cut out a piece of sheetrock to check)?
3. Continue to look into off-peak for now as a temporary cost saving until I could maybe afford a new more efficient gas boiler.

 

[pluckem]

No idea who installed it Pluckem. It's my understanding I'm about the 3rd or 4th owner of the house. I could try to dig around in the records I got from the others, but you know how that goes. Odds are probably slim I could find out. So, I don't know anything about how the foundation was insulated during installation of this system. I guess at this point I am looking into the following:

1. Would putting a floor sensor and a new thermostat help (detecting temp of the floor/slab vs. temp of the air)?
2. How well are my basement walls insulated (may have to cut out a piece of sheetrock to check)?
3. Continue to look into off-peak for now as a temporary cost saving until I could maybe afford a new more efficient gas boiler.

As far as insulation on basement walls.. you might be able to remove a trim piece around a window frame and see what they put in there. Or remove some outlet covers, or do you have access to floor truss area, might be able to get a peak there. However unless they just completely forgot to put in any insulation not sure it will matter. Financially would be pretty spendy to tear apart a finished basement to add more insulation.

As far as the insulation under the slab... Do you have a sump pump drain basin? you could maybe get lucky and see if its possible to remove the plastic basin and see what sort of insulation is under the slab.

Otherwise you would probably have to cut a hole into the slab in your mechanical room to confirm.

Might be worth a call to any install companies to discuss and see if they could do any troubleshooting or calculations to see if anything seems grossly off.

 

[remm]

Is the basement completely below ground? Did you notice any snow melting next to the house last year when it shouldn't have been? That would be a sign of not having the foundation insulated properly and losing heat out the sides, no way to know if they put foam down under the rebar/pex to insulate from heat loss underneath without ripping out concrete or talking to builder. You gotta hope they insulated properly as there isn't much you can do at this point if they didn't. Not having internal walls insulated properly would make some difference in heat loss, but if below the walls isn't done right, that's where you'd lose quite a bit of heat from the concrete.

I'd put a new thermostat in right away too, pretty cheap and definately wouldn't hurt.

 

[bigbrad123]

Is the basement completely below ground? Did you notice any snow melting next to the house last year when it shouldn't have been? That would be a sign of not having the foundation insulated properly and losing heat out the sides, no way to know if they put foam down under the rebar/pex to insulate from heat loss underneath without ripping out concrete or talking to builder. You gotta hope they insulated properly as there isn't much you can do at this point if they didn't. Not having internal walls insulated properly would make some difference in heat loss, but if below the walls isn't done right, that's where you'd lose quite a bit of heat from the concrete.

I'd put a new thermostat in right away too, pretty cheap and definately wouldn't hurt.

We didn't have a lot of snow around the house last year so it was hard to tell if I was losing any along the foundation. I'd tend to say no. The only reason I question the insulation piece in the walls is that in one of my bedrooms, the wall felt cold and it was a bit drafty around the window. That may have been more of a window issue and not a wall insulation issue. I live in your typical "newer" bi-level that is half above grade and half below.

I may have to just make a call to an install company and see if they can come and just check things out and make some recommendations. I know sometimes companies like Xcel will come out and do an "energy audit" and look things over, but I always figured those are just to try and sell services or products.

 

[Traxion]

My floor heat in the garage is controlled by a regular digital wall thermostat.

- - - Updated - - -



My parents had their NG tank water heater go out a little over a year ago, plumber put in a tankless as they said that's the vast majority of what they are putting in now. So far it hasn't been an issue for them, seems to get hot water to the tap faster than the tanked heater but that could be their imagination. I've been considering switching out my 75gal tank heater in my garage for a tankless just to save some space but haven't decided on it yet.

I am not 100% sold on tankless. We have put them in a lot of houses and it's about 50/50 of those who like and dislike them. Depending on location of your water heating device time can really vary on how soon you get hot water. Some also claim a cycle where you get hot, then warm, then hot water again. And this is even with the Rinai brand heater. We have very hard water and the plumbers claim maintenance MUST be done 1x a year, basically a vinegar flush and a few other little details. I am not sold on the long term cost & maintenance of the tankless. If you can find an 80 gallon Marathon (good luck on that) that would be my first choice to put in a house.

 

[REY_off]

From my research, yes a lot of systems run a temp sensor from the floor to the thermostat and also use a thermostat with an outdoor reset. The outdoor reset monitors the outside temp and kicks the heat on when it sees the temp drop. From my understanding, this is to compensate for the slow recovery time floor heat has.

I am currently running a regular wall thermostat and know other people using electric boiler systems with wall thermostats.

I might switch to a floor temp thermostat this winter

 

[bigbrad123]

From my research, yes a lot of systems run a temp sensor from the floor to the thermostat and also use a thermostat with an outdoor reset. The outdoor reset monitors the outside temp and kicks the heat on when it sees the temp drop. From my understanding, this is to compensate for the slow recovery time floor heat has.

I am currently running a regular wall thermostat and know other people using electric boiler systems with wall thermostats.

I might switch to a floor temp thermostat this winter

I just can't find a lot of literature saying for sure that using a floor temp sensor with a new wall mounted digital thermometer is better than a wall thermostat. Supposedly the outdoor reset monitor is supposed to help it be more efficient too by only bringing the floor up to a certain temp based on the temperature outside instead of heating it to the maximum temp each time. Mine is not connected, so I've considered connecting that too and see how it works.

 

[REY_off]

The guys at radiantec suggested using a floor temp sensor, they claimed it is the most efficient way to regulate hydronic heat. They specialize and deal with this stuff everyday, so take that for what its worth.

I decided to try the regular digital thermostat first. It works, but I feel like my system might cycle less with a floor temp sensor.

 

[327]

Who is your electric provider? Electric Coops rates are really getting high.

 

[Mocha]

To the OP,
We have installed 10-15 in floor hydronic electric boilers systems in our homes and rentals. We live in north central Minnesota so mostly sand. Off peak or ripple(duel heat) systems work fine with a back up. All our buildings have gas fire places for when the system is rippled and/or shut downs. Our electric rates for the off peak the last time I check was about 1/2 to 2/3rds for the off peak vs general service meter. Check with your electric company and find out what the difference in kilowatt is for each. Dig down outside a couple of feet to see if the outside walls are insulated. We have two different installations on our buildings. One is insulate the slab down and out a total of 4' so we have insulation going straight down 2' and then straight out 2' with no insulation under the slab (frost travels at a 45 degree angle). These homes have the cheapest electric rate but the power turns on at 11:00pm at night and shuts off at 7:00am in the morning so they heat up the slab and heatsink area of sand under the slab during the night and then all that heat is slowly released during the day. Very unresponsive system. You are at the mercy of what ever the temp is or isn't until the power is once again turned on or you open windows if too hot.

Our other buildings have the outside of the slab and completely under the slab insulated with no heat sink......insulation, pex tubing, rebar, and the concrete and gets rippled for periods of 2-4 hours with system shut down during peak hours of the day. This system is also on a duel heat rate from the electric company which is slightly higher than the true off peak.
Of the two systems the fully insulated slabs are much more responsive to room temp. The heat sink system is very unresponsive until the next day since the power is shut off for 16 hours at a time.

So knowing if your slab is fully insulated or set up like a heat sink would be beneficial. Then talk with the electric company and decide which way to power the system.

PS: In our area the electric rates have gone up quit a bit and I would love to be able to hook up NG boilers. If propane stayed at the current prices, which they won't, that would work also but NG rates seem to be the cheapest per BTU and most consistent. Good Luck and stay warm this winter!

PS2: How many square feet in the home, what is your heat source for the upstairs and what is your heating bill amount?

 

[huntinforfish]

As long as we're on the subject (not to hijack a thread), does anybody have experience with a NG tankless water heater? I've heard they do t work so well in ND because the water coming into the house is too cold. Broke ground on the house today so need to sort out this water heater thing ASAP.

My parents have been running one here in MN for years with no issues. Seems to me they are more popular every year.

 

[bigbrad123]

To the OP,
We have installed 10-15 in floor hydronic electric boilers systems in our homes and rentals. We live in north central Minnesota so mostly sand. Off peak or ripple(duel heat) systems work fine with a back up. All our buildings have gas fire places for when the system is rippled and/or shut downs. Our electric rates for the off peak the last time I check was about 1/2 to 2/3rds for the off peak vs general service meter. Check with your electric company and find out what the difference in kilowatt is for each. Dig down outside a couple of feet to see if the outside walls are insulated. We have two different installations on our buildings. One is insulate the slab down and out a total of 4' so we have insulation going straight down 2' and then straight out 2' with no insulation under the slab (frost travels at a 45 degree angle). These homes have the cheapest electric rate but the power turns on at 11:00pm at night and shuts off at 7:00am in the morning so they heat up the slab and heatsink area of sand under the slab during the night and then all that heat is slowly released during the day. Very unresponsive system. You are at the mercy of what ever the temp is or isn't until the power is once again turned on or you open windows if too hot.

Our other buildings have the outside of the slab and completely under the slab insulated with no heat sink......insulation, pex tubing, rebar, and the concrete and gets rippled for periods of 2-4 hours with system shut down during peak hours of the day. This system is also on a duel heat rate from the electric company which is slightly higher than the true off peak.
Of the two systems the fully insulated slabs are much more responsive to room temp. The heat sink system is very unresponsive until the next day since the power is shut off for 16 hours at a time.

So knowing if your slab is fully insulated or set up like a heat sink would be beneficial. Then talk with the electric company and decide which way to power the system.

PS: In our area the electric rates have gone up quit a bit and I would love to be able to hook up NG boilers. If propane stayed at the current prices, which they won't, that would work also but NG rates seem to be the cheapest per BTU and most consistent. Good Luck and stay warm this winter!

PS2: How many square feet in the home, what is your heat source for the upstairs and what is your heating bill amount?

My house is your typical bi-level, 4 feet of the basement or so is below grade. My basement is about 1150 sq feet. All finished. 2 bedrooms downstairs. We live in a residential neighborhood with few trees, so we get a pretty good northwest wind in the winter. Our alternative heat source is gas forced air. We do have the 6 inch circular vents downstairs (3 in living area, 1 in each bedroom).

The boiler we have is a thermolec. No idea how old. We have a typical old fashioned circular mercury thermostat downstairs that controls the floor heat. There is no floor sensor and the outside temp detection device is not connected.

I have no idea about foundation insulation. The walls in the basement northwest bedroom feel cold, but none of the other walls do. I haven't done a lot of checking yet re: insulation around windows and in the walls.

Our electric Company is Cass County electric, but for gas we have to go through Xcel. CCE told me that the cost for off peak would be almost 1/2 less. I think the #'s they gave were $.10 per ?? (kilowatt?) and the off peak rate is $.055. I just don't want to spend the $ to install off and off peak meter if it really won't make a difference, won't allow it to warm up enough, OR there could be another option such as installing the outside monitor and new thermostat/floor sensor that would help a lot. Maybe doing those two things would help significantly?

Would love to get a natural gas boiler but the "good ones" aren't cheap. I probably could afford a cheaper brand (ie: brand they sell at Menards), but people have discouraged me from buying those brands. I'd like to try a couple other options before breaking down and spending $3 or $4k.

 

[BrokenBackJack]

As long as we're on the subject (not to hijack a thread), does anybody have experience with a NG tankless water heater? I've heard they do t work so well in ND because the water coming into the house is too cold. Broke ground on the house today so need to sort out this water heater thing ASAP.

when we lived on our farm i finally bought a propane tankless water heater. It took a little while longer to get hot water to the faucet but not that much longer. The big deal was how much less propane we used than with the large tank propane water heater. You should back flush them every couple of months. Not a big deal to do. We liked it but the choice is yours.

 

[REY_off]

My house is your typical bi-level, 4 feet of the basement or so is below grade. My basement is about 1150 sq feet. All finished. 2 bedrooms downstairs. We live in a residential neighborhood with few trees, so we get a pretty good northwest wind in the winter. Our alternative heat source is gas forced air. We do have the 6 inch circular vents downstairs (3 in living area, 1 in each bedroom).

The boiler we have is a thermolec. No idea how old. We have a typical old fashioned circular mercury thermostat downstairs that controls the floor heat. There is no floor sensor and the outside temp detection device is not connected.

I have no idea about foundation insulation. The walls in the basement northwest bedroom feel cold, but none of the other walls do. I haven't done a lot of checking yet re: insulation around windows and in the walls.

Our electric Company is Cass County electric, but for gas we have to go through Xcel. CCE told me that the cost for off peak would be almost 1/2 less. I think the #'s they gave were $.10 per ?? (kilowatt?) and the off peak rate is $.055. I just don't want to spend the $ to install off and off peak meter if it really won't make a difference, won't allow it to warm up enough, OR there could be another option such as installing the outside monitor and new thermostat/floor sensor that would help a lot. Maybe doing those two things would help significantly?

Would love to get a natural gas boiler but the "good ones" aren't cheap. I probably could afford a cheaper brand (ie: brand they sell at Menards), but people have discouraged me from buying those brands. I'd like to try a couple other options before breaking down and spending $3 or $4k.

The tankless hot water heater that Radiantec sold me (said they have used these with very good luck) was about $1200.

Here is a link. I questioned them a lot before I went ahead with the purchase. Althought modulating boilers are more commonly used, tankless water heaters are being successfully used. This model has a 10 year warranty when being used with hydronic heating.

http://www.americanwaterheater.com/residential/tankless/gt-240-nih/

 

[Farmer]

Check with your utility companies they may have programs/packages to help you out financially

 

[bigbrad123]

The tankless hot water heater that Radiantec sold me (said they have used these with very good luck) was about $1200.

Here is a link. I questioned them a lot before I went ahead with the purchase. Althought modulating boilers are more commonly used, tankless water heaters are being successfully used. This model has a 10 year warranty when being used with hydronic heating.

http://www.americanwaterheater.com/residential/tankless/gt-240-nih/

So maybe I missed this, but do you run floor heat using the tankless water heater? I read on their website that is becoming more common, and have heard that from others as well. $1200 is definitely better than 3 to 4K!!!

 

[Mocha]

Hey bigbrad what are we talking about as far as heating bill? Not total electric but just heating if you can separate on you bill and if you can't what is your total bill during a typical winter heating month?

I am not sure how changing out a thermostat will lower your costs. If you keep temp where you want it, a better newer thermostat will keep it closer with less variation but I fail to see how it will save you money unless it is programable so you can automatically adjust it down during hours when the comfortable temp is not needed. BUT then you run the risk that the boiler system will take a bunch of time to readjust to comfortable temp range. If it keeps up with the heat needed for your comfort then your problem is with the BTU cost to keep it where you want. Insulation, wind breaks, windows, types of power/boiler.........IMHO