Radiant Heat not warming house

[audralynn]

Hello:
Hello:
I installed radiant heat in my home this fall as part of a 1st floor renovation. We gutted the first floor to the studs and rebuilt, insulating and updating the house. The heat is installed between floor joists of the 1st floor (basement installation). I have a cast iron boiler. When the system runs (because the floor went below the set point) the water going into the system is 125 and coming out is 120 so we are within the 5 degrees. My floor has a set point of 74. I have an infrared thermometer so I know the top of my floor is typically 5 degrees off of that, so around 69. My floors are hardwood (pine) with a 3/4 floor board and then 3/4" pine boards. The PEX tubing was installed per directions (tubing, aluminum plates, foil insulation (foil pointing toward the aluminum plates) and then insulation around that.
So my problem is that the house is not warm. My room temperature is typically 12 degrees lower than my set point – so if my set point is 74 then my room is about 62 – it has even been lower the past couple of days b/c we have a cold snap here in Maine. I am concerned because well it’s cold a lot here in Maine. I thought I was losing heat to the upstairs (where there is no heat at all) so I put an old army blanket in the stairwell. I have to think that is working b/c its 42 degrees in my rooms (it’s been awful for sleeping!) but my downstairs still has the 10-12 degree difference. I turned the set point up to 80 because I am freezing but I don’t think it’s supposed to be that high. I can’t figure out why the room does not get warm. We do not yet have the mop board (floor board trim) around the rooms, but I covered up the few places I could feel a draft coming in with more army blankets. We are going to drill into the floor a bit more and put the floor sensor probe further up so we can get the top of the floor temperature closer to the set point but I don’t think those few degrees are going to make up for the 12 degree difference we are experiencing. The only other thing I can think is that the water going through the tubing is not hot enough. They sent me specs that said it could be up to 150 but that seemed high and before I did that I wanted to check and see if anyone else has had this problem. This is our first experience with radiant heat but we(my father and I) have tons of experience in heating and renovating homes – but this one has us baffled.

Thanks!
Audra

[resercon]

The radiant floor heat will probably work fine once you provide heat for the second floor. In other words the radiant floor heat on the first floor cannot produce enough btu/hr. for the first and second floor. This coupled by the fact that radiant heat is influenced by proximity to the heat source. The closer you are to a radiant heat source the more heat you will sense. The further you are away from that heat source the less heat you will sense. There's no wonder why you are freezing upstairs.

The manufacturer who sells the radiant floor heating system also sell a radiant baseboard that connects to pex tubing. Easy to run upstairs.

[audralynn]

Thanks Resercon! I think I mixed up my question by adding in the part about the upstairs. My plan is to not add heat to the second floor. We are planning on gutting and renovating that level in 2 years and I have lived for the past 3 years there with no heat upstairs, although it was never quite this cold, so I was hoping to continue that way. I have blocked off the stairwell that goes to the upstairs to keep heat from going up there and I still can't get the downstairs warm.

I can run a piece of baseboard upstairs, but I since I currently have the upstairs blocked off from heat rising I feel as if that isn't my problem. Should I just try it as a process of elimination to figure out why I can't get the downstairs warm?

[resercon]

If that is the case, you are going to have to insulate the ceiling of the first floor. If you know how to do a Heat Load calculation you wold consider the first floor without attic insulation at present and would explain why you cannot get it up to desired temperature.

[Bud9051]

Hi audralynn, resercon has got it right, the one floor of radiant will have difficulty providing enough heat for your whole house. I would suggest pushing the water temp up to give you more heat capacity, and then doing all temporary insulating you can upstairs. When you feel a draft upstairs, it is really bad, as most air is normally leaking out, not in, stack effect. Blocking air leaks is frequently easy and inexpensive. There are many lists on the internet as to where to look. Pick up some incense sticks for smoke and test baseboards, windows, electrical boxes, and lights. Warm goes out the top and pulls cold air in the bottom. Put some plastic over the upstairs windows, and down if you want. These are the basic steps for energy efficiency and weatherizing, which you should get good at, as it is a lot easier to do while remodeling than after. 22 outside in Bangor Burrrrr
Bud

[warmsmeallup]

Yes, the cold air dropping down from the second floor is affecting the first but, I think it goes 'deeper' than what's been mentioned here.

What's the temperture of the basment below the first floor? Is it heated? If you needed insulation, chances are it's not. What is the insulation you have installed between the joists below your installation of radiant? Is it there just R-19 batting below, a reflective insualtion then batting? What's the total 'R' if there's more than 1 type? What's the design; Radiant panels, 2" drop to a reflective barrier then a batting, etc..

[audralynn]

Sorry I have been delayed getting back here... we have been busy putting heat upstairs!!! Before we did anything we borrowed some space heaters and heated the upstairs and wouldn't you know it the downstairs got warmer too... the upstairs heat finishes tomorrow - just in time for another cold snap next week.

Thank you warmsmeallup for your reply!! The basement downstairs is not heated, we use it for food storage (canned foods/ winter crops, etc) so we don't heat it. But the radiant heat was installed with aluminum plates to spread the heat, then reflective insulation then fiberglass batting (friction fit). The basement has been acting as we expected and the floor reaches the correct temperature and works the way it should, we just couldn't get the room warm.

I think this upstairs heat should do it.. if not I will be back, but we did have a professional look at our radiant installation and it all looks on track!

Wish me luck - its gonna be a cold winter!

[warmsmeallup]

I'm glad that worked out for you. We just finished an installation where the radiant system installed wasn't adequate as primary, though it was supposed to be, and we were brought in to retro-fit another system from below. Then, the reflective and batting was installed below us and all is well.