Radiant heat usage question

[B&H]

Hello,

I own a 2-bay auto repair shop in Central New York. This summer, I had the floor replaced and installed radiant floor heat with a Buderus boiler.

We removed the ancient hanging gas forced air heater.

I'm not sure the radiant heat is going to be enough when it gets really cold, and the 2 overhead doors open to let in frozen, snow-covered cars. I will have to wait and see on that.

Right now, I am concerned with what to do in regards to the floor heat, as the temperature slowly marches downward heading toward winter. The nighttime lows are in the 30's, and the daytime highs are in the 50's and 60's.

We need heat in the morning, but by noon, really would like to open the doors and enjoy the remaining fall warmth. The same thing is going to happen in the spring.

In the meantime, does anyone have any suggestions on what to do during this temperature transition time? Keep the boiler on at a lower setting, turn it on/off like we did with forced air, add another forced-air unit, or ???

Thanks!

 

[Jeepskate]

Radiant is a set & forget and you should probably have it running by now to start getting the slab up to temp without the 'heavy lifting' of heating an already frozen slab. You absolutely do not turn it off and on and for the best efficiency you shouldn't bump the temp settings up & down...set it and forget it. Since you have a repair shop and will be constantly opening the doors, you should put an auxilliary forced air heater in to handle recovery.

 

[tdkkart]

A couple things will be different now that will make a difference in where you have your thermostat set, and the recovery time after you open the doors.

Number 1, since the people working in the shop will have warm feet they will feel warmer overall. I'll bet that you'll be able to set your thermostat 5-10* cooler than you did before. The floor temp will end up 5+ degrees warmer than your desired air temp, so do not be surprised if you find your guys laying on the floor more often.

Number 2, with the old system, when you opened a door to move vehicles in and out your heated medium, the warm air in the shop, got exchanged with cold air from outside which had to be re-heated to get you back to your comfort level.
Now the floor and the objects in the shop are your heated medium, and will remain warm when the doors are opened. You will notice that your recovery time is much less.

You will notice that with a heated floor all the equipment in the shop will be warm all the time. Your tools, equipment, work benches, hoist etc will all be much warmer making working conditions much nicer.

Check the temp of your floor now using an infrared temp gun if you have one. If the floor temp is much below what your desired heating temp is, you need to start the system now.

 

[B&H]

The system is running, and the last several days, I tried to pay attention to when the boiler runs. It's a GB-142 w/ outdoor reset, I've 'shot' the floor many times with the IR gun, when the system was initially started.

I have the stat set at 60°F, and the nights have been in the high 30's, with the days reaching 55-60. What I've noticed in the past several days is that the boiler is off when I get to work at 8am. By noon, we've opened the doors and left them open until 5 or 6 PM. The boiler never came on. When I left at 9:30 PM, the floor was at 71°F, and the shop was at 70. The outside temp was 50, and the boiler still had not come on.

While I now have learned to leave the stat alone, and I am confident that opening the doors like we have been won't make a big difference in fuel costs, the jury is still out as to what happens when it gets real cold and we start bringing in frozen cars.

My limited experience in radiant floor heat is that it comes as advertised - incredibly comfortable, even heat, warm floor, warm feet, etc. I have worked on cold, **** concrete floors for 25 years, and replacing the 70 year-old wretched concrete floor in a shop that I bought 3+ years ago with new concrete, epoxy and radiant floor heat really has made for a comfort and cleanliness level that I never thought possible.