2500 gallons 3500 sq ft

Oilhog

Thanks, no the first winter I was here the main 5 ton unit didn't work at all and the other was switched off (no power). The third undersized one is visible from my computer and very audible. I'm going to say I'm rather certain that's not my problem.

pedmec

I would just confirm that as i have found that to be high consumption problem. The last one i found the women was so mad at the fuel bill she sold the house. I was there to see if i could find the issue as they didn't want the sale to fall. Funny thing is they just kept adding more air conditioning lmao.

EBEBRATT-Ed

If the system is undersized it's going to run constantly to try and do a job it can't do.

Picture this:

Park your car against a big tree, put it in gear and floor the gas pedal. Your burning a lot of fuel but just spinning your wheels

Hot_water_fan

I have approximately 870 square feet of glass, with 164 North facing, 475 South facing, 144 East facing, and 87 West facing.

Ah. That makes more sense. And these rooms are all heated? New or old windows? Single, double, or triple pane windows? I think 2500 gallons/year might be the price of your views.

WMno57

Buy 870 square feet of thermal drapes. Open them every morning. Close them every night. Mid Century Modern? I had a small one, 1200 sq feet of floor space. Floor to ceiling windows.

hot_rod

The red flags for me are the sunroom with possibly an uninsulated slab, lots of glass, high load

Garages can be a tough load with a lot of infiltration around the door. A blower door test in that space would show how much leakage you have As Scott mentioned, that would increase the load in the room above. Since that is under heating it may be related to a leaky garage

The remote air handler that struggles to provide adequate heat may be short cycling the boiler driving efficiency down, fuel use up.

Duct blasters can be connected to the system to find the leaks in the ducts.

An infrared scan if the house in a cold, heating day can sometimes show missing insulation areas

With the fill valve turned off, does the boiler pressure drop?  If it does, somewhere you have a leak. Under the greenhouse for example?

Oilhog

Regarding the glass, 219 square feet of the 475 South facing windows is the sun room glass.

Regarding the garage, recall that the first winter there was no garage heat, but still wild consumption.

The sun room is on the Southeast corner of the house, on the Northeast corner is the dining room, and sandwiched in between is the kitchen. These three rooms represent the upper section of the split level main floor of the house. This area has a thermostat in the dining room which blows heat from the lower air handler into the dining room only. The sun room has a thermostat which only activates the radiant floor heat. The kitchen only gets heat from these two adjoining rooms (plus whatever wafts up from the lower level), and so far only the dining room, since the radiant has remained off. Each morning the kitchen is rather cool, the sun room is cold, and the dining room is at 68 per the thermostat's setting.

As an experiment, we hung up thermal curtains for the past two nights (low in the 30s then 40s) to see the difference. The kitchen felt very significantly warmer than usual, in fact roughly equal to how the dining room felt (no thermostat so no precise temperature) and the sun room was down to 55 then 57. We are going to get an estimate on French doors to close off the sun room as a result. The floor heat is filled with glycol, but I can set a minimum temperature anyway. Any recommendation as to what temp is best to prevent freezing, be efficient, keep the unit in good functioning shape?

Hot_water_fan

It depends on your goals for the sunroom. For efficiency, off is most efficient, but the lowest thermostat setting is fine as well. If there are any leaks, the glycol % will be lower than expected, so keeping it at some minimum temp insures against that. The heat loss of the kitchen increases as the sunroom temperature decreases so that’s another variable. I can’t believe your house was built with an unheated kitchen. 

WMno57

@oilhog , is your entire system glycol, or do you have a heat exchanger between the water boiler and the glycol floor?
If the entire system is glycol that will cost some efficiency. Glycol takes heat from the boiler less readily, so more dollars up the chimney.

hot_rod

If the sunroom is open to the rest of the home, heat will travel to that space based on temperature differential. So the colder the sunroom the more heat from the other rooms will travel to that cold room. Probably not enough to warm the sunroom if it has high heat loss. So the rooms connected will drop also.

Hot goes to cold, alway

The rate at which it moves is based on temperature difference

 
I think you are in the right path with insulated  doors on the sunroom

Oilhog

Glycol is only in the radiant portion, I'm told.

I will pursue the isolation of the sun room and update after.

Thanks to everyone for your help.

BobZmuda

You’re also heating your attic. A visual inspection is not an appropriate way to check for duct leaks.  

Blown in cellulose will not prevent air movement through it. The air movement from leaky ducts will negate the r value of the insulation around the ducting. 

Here in the land of inspectors, we have to do a blower test on the ductwork. You’d be surprised how much even new ductwork can leak. 

There’s a paint of sorts you can apply at the seams that will help seal things up. Caulking works too of course. You should seal them up and then insulate them.  Cellulose on top of the ductwork would work only after proper air sealing. 

Sounds like you’ve got a good handle on the other things to check. I wish you good luck!

oh, one more thing. Milwaukee makes an affordable thermal inspection camera.  With that much oil use it would be worth buying and investigating yourself. You are after all the one paying for the oil, not the contractors who look at your fuel bill and shrug.  No offense to them, this is a highly specialized area of expertise.  

gmcinnes

You have multiple zones, yes? Has anyone looked at the run time of the boiler vs. each zone?

After much fussing here I was able to identify that about 1/3 of our BTUs go to a zone that heats 2 smallish rooms above our garage. It probably only makes up about 1/10 of the square footage.

FWIW I'm also in CT, in a circa 1840 house, with oil/hydronic heat and a unit heater in the garage, and really good insulation work done by the same contractor as you. Our oil usage was probably around 1500 gal last year.

Heavy curtains are underrated as a heating/cooling tool

bburd

Ductwork should be sealed with duct mastic, with mesh tape used to reinforce it where the gaps are wide. This makes a permanent seal. It’s widely available at home centers and supply houses.