Question on home heating furnace

I think Alexander had it correct. Your old ducting is the reverse of what is now used, at least in this area. Warm air would be sent via floor diffusers at the outside walls and under windows. Return air would be high on an inside wall. This reduces the variation in room temperature as the furnace cycles. The poor thermal condition of your house also will cause rapid temperature changes leading to cycling. The hysteresis setting may be correct for a modern house but not one that loses heat so rapidly. Unfortunately setting for a greater differential will result in greater swings that you will feel. Get some storm windows. See if you can seal up any air leaks. If you have a basement insulate the box joist spaces. Next spring put blue or pink foam against the basement walls down 3' into the ground and above grade cover it with some of the fabric/resin systems almost all the way up to the framing. If you are in a termite area use termite shielding, or an inspection gap, or treat the ground around the house so they can't go up between the foam & the masonry.

If you do most of the work except termite treating you will probably recover the material cost in a few years fuel costs. AND your furnace will cycle less.
 
I have to agree with Dabbler, I have my fan running year round with the new smart thermostats there is a setting that you can set the fan speed as well. Mine setting puts the fan in a slower speed so you don't even know its running. I also noticed that in the summer if you have return vents in the basement open it will pull the cooler air out of the basement and help with the air system. Not only it also keeps the air in your house being curculated all the time.
 
Since this appears to be a new problem after a number of years, likely it is a failure of the thermostat with maybe some environmental changes in the house.

I run a whole house HEPA filter off the furnace, at all times. It does help balance the hot and cold spots in the house.

As I have been adding insulation where I can the bills have been getting smaller. The most recent change was to use Dri-core panels on the basement floor. Once that cold concrete was covered, the temp in the basement came up to mid upper sixties from 60-61. Sweet!
Pierre
 
Flyinfool said:
Since my house was built in the late 1800s, still has the original single pane windows, and only as much insulation as I could sneek into the walls, I am thinking of a 60K BTU for next time.
Click to expand...
Sounds like our house. Built in 1947 it had single pane windows and skimpy insulation by 'todays' standards. The house was originally heated by a monster coal furnace. The central ventilation fan was on full time. No chance for cycling with that set up cause there was no thermostat.
Over the years the insulation was upgraded and heating was switched to oil with a thermo pump added eventually. Upgraded insulation measures (triple pane windows, thicker walls, blown in insulation and sprayed on PU) were essential to slow heat loss to levels compatible with thermostat control.
I really don't see how to solve your short cycling problem without slowing the rate of heat loss to the outside.
 
Short cycling is almost always caused by improper sizing of the equipment. Couple that with an extraordinarily inefficient house and there will be a lot of issues. A lot of people like the "charm" of old houses, but the mechanical side of them (plumbing, insulation, heating, cooling, air quality, electrical, windows, etc.) are usually a disaster. I know that moving may not be an option, so the best you can do is to have properly sized equipment and utilize stop gap measures to minimize energy loss.
To analyze your system and develop a corrective plan would require some work. If you want to contact me, I would be glad to help as much as possible. I am not a HVAC contractor or specialist, but I have built two very energy efficient houses in the last 12 years and have studied energy efficiency a fair amount.
My most recent house (last year) is 3400sq ft total, including the walk out lower level. 4-4.5" of closed cell foam in the walls. All penetrations in the attic sealed with foam and 24" of blown cellulose. Triple pane windows from --->Accurate Dorwin<--- which also have fiberglass frames that are foam filled to reduce thermal transfer to a minimum. There were days last year that that it was -20F outside and my house only lost 2F between 8am and 4pm when the thermostat lowered to account for no one in the house during the day.
Lots of advice in this thread. Some good. Some not so good. If you want to solve the issues you will need to look at your house as a "system" rather than just one issue.
 
Last edited:
I would agree that trying to hold temperature to 1/2 degree in an old house is an exercise in futility. Even if holes contributing to drafty conditions are sealed up, single pane windows will set up convection currents which contribute to air movement within the house. In addition to setting the thermostat for a longer cycle time, consider the location. A thermostat shouldn't be located near a hot air register or near a spot where air currents may affect it. If necessary, consider closing or throttling back hot air registers in the room where the thermostat is located. Another solution would be to mount the thermostat on a thermal mass. I would use a shallow box , probably aluminum and a more massive back plate. The box will tend to shield the thermostat from air currents and the thermal mass will have to be heated/cooled along with the thermostat, creating hysteresis in the cycle.

Our house is also over 100 years old with about 1700 sq. ft. of heated space. When I originally moved in, there were single pane windows with air gaps and no insulation.. We heat with a wood furnace and at first, I would burn 20 cords of wood in a season. Blowing cellulose insulation in the walls, replacing the old windows with modern windows, and genearrly sealing up any air gaps have reduced that to around 4 cords/year.

We have a 93% efficiency backup L.P. furnace which is used for heating when mild outside conditions don't warrant building a wood fire or when we leave for an extended time. We burn about 150 gallons of L.P. a year. Our L.P. furnace is a 120kBtu input/112kBtu output furnace and has performed well for us over the past twenty years. Even in the early years with poor windows and drafty conditions, there has never been a problem with short cycling. The thermostat controls to +/- 1º.
 
Flyinfool said:
The more research I do into this the more screwed up I think the whole system is.

I set up a temp probe right next to the thermostat to see what the actual temps are doing.
The thermostat is trying to hold temp on this old house to within 1/2 degree. the stat asks for heat when the temp drops by 1/2° and shuts off when it reaches set temp a half degree higher, the room then climbs a half degree more while the furnace is in cool down mode.
There are no adjustments of any kind on this stat, I even took it down to check the back.
I guess this means that I need a new stat.

It is not the furnace hitting over temp It is defiantly the stat that is doing it all, I have an indicator to tell me when the stat is asking for heat.

I was hoping to be able to do a new furnace next summer anyhow, it has to be a summer job cuz I want to move the furnace to a different location in my shop, more out of the way and with the rest of the appliances (washer, dryer, water heater, laundry tub). This means plumbing changes to make room and a lot of duct work and even some structural work on the house. but it will make a lot more room in the shop.
Click to expand...

I just looked at the installation instructions for the LUX thermostat on our wood furnace. In addition to the switch on the back for electric or fuel heat, there is a software setting for hysteresis from 1 to 4. It is accessed by pressing NEXT and HOLD buttons simultaneously while in the RUN position and UP or DOWN to change. Pressing NEXT will exit. Your thermostat may have a similar routine.
 
Last night we watched the comedy movie “The Money Pit”. The older the house, the bigger the pit and bigger the pot of gold required to fix it.
I would hate to think how much I have spent to date on updating this 70 year old house. All windows and outside doors. Added R50 to the attic, 13 bales of R28 to start in the first winter, and 2” foam on the basement walls and the Dri-core panels on the concrete floors. This reduced the bills right away.
Replaced the antique heat pump with a Bryant Ultra high efficiency furnace, moved some of the duct work around as well, that cut the power bills and gas bills by more than half again!
When I rebuild the kitchen, which is the windward wall, I will strip the wall down to studs and spray foam this wall. It is a total 20% of the outside wall. This will change my cabinets from ice box in the winter and toaster in the summer to something a bit more moderate. Stopping the air entrainment and stiffen the wall. The original insulation is R7 papered on both sides and poorly fitted.
It is an ongoing process and a continuously moving target, as cost to heat and cool keep going up.
Pierre
 
My 110 y.o. money pit cost me $25K and came with 12-1/2 acres of land. I have put about $100K into remodeling with $50K going into the kitchen (although the kitchen is a world class act). There is also a very large amount of sweat equity. The property is currently assessed at $200K which is most likely under market value. We have a home which is comfortable and reasonably up to date regarding plumbing, and electrical, and is structurally sound enough to outlive me.

Personally, I would prefer the older home built with quality materials over the new home built with skimpy materials by builders cutting corners to boost their profit. Whenever a tornado rips through the area, the houses n the path look like a pole of pick up stix. If mine ever gets hit, it will be more like Dorothy's house in the Wizard of Oz.

One definite advantage of buying a fixer upper is that the sweat equity is tax free. It is a great way for someone starting out with more time than money to build their assets.
 
I disagree about the older home and quality materials. One of the only advantages I can think of regarding an older home is that a lot of the "sheathing" they used were individual boards nailed to the outside walls or to the roof trusses. I have seen so many "quality" old houses with sagging floors and poorly constructed stairs, not to mention there is not a straight wall or floor to be found. If installing a built-in, many provisions need to be made for significant irregularities. A real PITA. Most old homes have balloon framing also, which is a fire disaster waiting to happen.
To each his own though. Old houses just are not my thing. A properly constructed new house provides a level of comfort that I really enjoy.

I forgot to mention that my new house also used --->T-Studs. A new and significant inovation.<--- In fact, my house was the first in the state of WI to utilize them.
 
You must log in or register to reply here.
Back
Top