New house furnace question

[Cars&Classic]

Just had a new house built over the summer, love it and konw sometimes things arent perfect, but the heating guy and I are not working thing out.

one thing he wants me to do is run the fan/blower all the time. not have it come on automatically when the furnace kiks in. What do you HVAC guys think of this? it worries me to have an electric motor run 100% of the time. fire hazard? burn up sooner? maybe they are made for this now.

the house is a large 2 story + a basment. the basment is insulated but unfinished at the moment. and the heat is on in the basment.

the total heated sq ft including the basment is 4,900sq ft.
one of the bigest problems is the difference in tempurture from upstairs to the main level it gets to be unbarably hot upstairs, and is still uncomfortably cool on the main level. with my temp gun it seams to be 10-13 degrees differance. in the morning after a cold night. and we are not even into winter temps yet! The house is well insulated and not drafty, and was inspected and certified 5 star rating the level was "70"

the house should have had a zone heating sytem and it was an option but an extra 4k. the builder is saying they will stand behind it and they have a 3 deg warrentee. the heating subcontractor is the one that dosent want to do anything, he says the anwer is to run the fan 100% of the time.

what do you guys think?

 

[brewchief]

Before answering the question about running the blower all the time I would want to know the make and model of the furnace. A few pics of the system would help as well.

 

[Cars&Classic]

it is a bryant

 

[rickairmedic]

Cars as Brewchief says get us some model numbers as well . There will be a sticker on the front of the evaporator coil sitting ontop of the furnace with a model and serial number on it . There will also be model and serial number information on the inside of the furnace . My biggest problem with what I am seeing is if this is your only unit you are trying to heat and cool 4900 SF with on a good day 3750SF worth of HVAC equipment . This is assuming you have a 5 ton system which is the biggest residential system you can get . I have run my blower full time " when I heated the house with electric radiant heaters " before swmbo and the kids moved in . My own oppinion is it does less harm to the motor running full time then it does leting it run only when the system is running . Much like a car motor the initial startups are what hurts these motors ( as well as dirty systems ) . With that said the only time I recomend this for customers is when they have a multi story home and a good working existing system that was not done right from the beginning . I wouldnt own a 2 story home woith a single HVAC system in it . I would bet if you had 2 seperate 3 ton systems one upstairs and one downstairs you wouldnt have a problem .


Rick

 

[HVAC Phil]

I run my blower in the house year round, but it is a variable speed motor(air filtered 24/7 for wife allergies). The system in your house is likely too small, poorly designed duct work as well. Have you balanced the system at all? Shut dampers going to 2nd level off 1/2 way, wide open for 1st floor. Reverse this process in the summer. Is this a "track" style built home? Those builders cut corners, and HVAC is one area they cheap out on. Bottom line, system is too small, zone system woulda covered that up, unless both zones all at same time. As Rick said, you should have 2 seperate systems in the house.

 

[Dragster Racer]

x2 on the balancing of the system. We have a two story with a great room and open loft. If there is anything that would be tough to ballance with one system, it is that. But it isn't a problem for us. We don't run our fan all the time, but we did for the first couple months. It helped to get all the dirt out of the new house. We changed that furnace filter every week for two months, and it was full of stuff every time. I don't know how much you want the basement conditioned, but we have all the ducts off in the basement. That will buy you some capacity if you aren't using it. We have about 2200 down, 750 up, and a full exposed basement, and our Goodman has no problem on -20 and windy days. When we have a fire in the fireplace (mostly sealed unit) we run the ceiling fan in the great room or the loft gets overly hot.

 

[Cars&Classic]

I will get the model number and exact Sq ft for each level today.
yes it is a track home, I am actually a realtor and of all the builders I work with this one seams to build the best home and put the most effort behind the process. I guess we will see if they can make the HVAC contractor fix it righ?

we did try to ballance, we acctually have every vent completely closed! on the top level and open on the main. even with all the vents closed it is about 10-12 deg differance in the am. it hasent been cold here during the day yet so we dont notice it till night
we also tried opening the basment ducts, and that hellped a little. but the basment seams chilly as well.

it is a walk out basment so the back side is exposed. the builder insulated the basemnet walls about 6 feet down all the way around. they also covered all of the wood frame walls on the back side with a insule board.

there is a separate company that came in and ispected the insulation for the 5 star rating. they scanned the walls with a infared gun type thing, then sealled the front door with a fan assembly and pressurized the house. to test for loss?

according to there charts the house seam to have a high rating, the local gas company even gave us a several hundred dollar rebate based on the report.

that being said we recieved the first heat bill yesterday, wow! double waht I expected.
used 245 therms, 246 CCF in 28 days. that is a little scary because we havent had any cold weather yet. nothing in the teens, and only a day or two in the mid 20s.

found the %star report
condutioned area 4893 sq ft
conditioned volume 43887 cubic feet
fuel -fired air distribution natural gas 92% EFF
duct leakage to outside 27.00 cfm
vent system none, programable ther: yes

building
ceiling flat R38
exposed floor R31
valt N/a
Above grade walls R14
foundation walls R11
window type u-35, SHGC-34
infiltration rate 1618 CLG:1618 CFM50
method blower door test

dont know how accurate these reports are but it estamates for our area that this house should use 887 therms for the average living style, our november bill was 245! and it isent even cold till jan!

 

[HVAC Phil]

Do you have the damper is basement closed or the vent in floor? Closing the vent in floor does nothing to balance the system, air is still directed to that run. You have to close the actual damper on the heat run at the trunkline.

Also is the there enough return air vents in house? You should have atleast 12 single returns total.

 

[HVAC Phil]

I quit doing track homes, i leave those for the hacks. Builder wants cheap, they could care less how it looks/works. System is too small, and i would bet the ductwork is not sized correctly as well.

 

[wrenchguy]

No matter how many zones, "warm air rises and cool air sinks" especially when one has multi level homes with open staircases. Its our modern times with all the openness that these issues come up. Back in the day doors closed off every room and level for a reason. good luck.

 

[Dragster Racer]

Do you have the damper is basement closed or the vent in floor? Closing the vent in floor does nothing to balance the system, air is still directed to that run. You have to close the actual damper on the heat run at the trunkline.

Also is the there enough return air vents in house? You should have atleast 12 single returns total.

I'm not following. If you close off vents, and no air comes out, then why is this not pushing more air elsewhere, and aiding in balancing?
I am also wondering about returns at this point.

 

[Teken]

One thing to take note: If this home was literally just built you will have a lot of humidity. It takes more energy to heat cold damp air.

This is why I installed a dehumidifier and ran that son of ***** 24/7 for two months.

Why??

Because during the first winter season, all the exact same homes in my area had heating bills double, triple of mine.

Having said all of this, I agree with all the previous posters about sizing, and the correct way the HVAC should have been done.

Teken . . .

 

[HVAC Phil]

I'm not following. If you close off vents, and no air comes out, then why is this not pushing more air elsewhere, and aiding in balancing?
I am also wondering about returns at this point.

If you just close off the vent in the room, you don't actually divert more air anywhere, air is still moving from trunkline to the actual vent in floor, then stopping. You have to close the "damper" in the heat run, in the basement, near the trunkline. Now the air will just travel along the ductwork till another heat run "grabs" it.

 

[Cars&Classic]

no dampers, I am glad you think it needs it. I asked already. I am lucky the builder seams to be behind me, even though the sub is fighting it.
the houe was started last march, we moved in in august. the builder did run a dehumidifyer for 2-3 months 24/7.
there are phtos of the garage in my profile, http://www.garagejournal.com/forum/album.php?u=78888

I am working on the furnace for the garage myself.(thanks for your help on that also HVACphil and others)

here is a link to the house photos, we added doors and reexcavated the back after we moved in to make it a walk out basement.
The garage has a drive through bay with a "Car Patio" behind it.
http://www.visualtour.com/photoedit.asp?T=2564526&S=47898236

 

[HVAC Phil]

See, the no damper issue worries me. They tried to save $20 bucks there on the install. Count the returns in the house, and measure the return trunk size. If you don't have enough air coming back, the supply air never gets there.
I put dampers in my main trunk lines too, if the duct goes both ways from the furnace. Gives me alot of control of the system. I usually never get more than a 2* difference from up to down temps.

 

[wrenchguy]

"the houe was started last march, we moved in in august. the builder did run a dehumidifyer for 2-3 months 24/7."

Why? Do ur windows sweat on the inside? Hummm, u haven't had that cold weather yet? Whats under ur foundation? Clay or sand? Just asking for the future.

 

[Dragster Racer]

"the houe was started last march, we moved in in august. the builder did run a dehumidifyer for 2-3 months 24/7."

Why? Do ur windows sweat on the inside? Hummm, u haven't had that cold weather yet? Whats under ur foundation? Clay or sand? Just asking for the future.

The drywall alone has a ton of moisture in it. I would think that would be taken care of in a month or so.

 

[Cars&Classic]

we hava a lot of hardwood, they couldnt install it until the moisture content reached a certain level in the sub floor. I know that was part of reason they were runnnig it.
clay here

 

[kippieland]

Sounds like you may have some bigger issues besides the motor running question. We just replaced ours with an efficient model that has a fan running the all the time...costs next to nothing and our energy company gave use some breaks on it because its considered a green thing. I love it so far and we now have an electrice heatpump paired with its super cool!

 

[JimL]

Your basically screwed. Only way to make it work right is to redo the duct system. See it all the time, hack work or people trying to save a buck. Most the tract homes you see are rubbish anyway. Cheapest way possible.

We have done several 3 level homes on one system, and they have worked flawlessly. Zone everything with dampers in the trunk line, each level has its own supply trunk and return. Cost more but it works and each level has no trouble maintaining temperature.

 

[Chaz]

If you have an upstairs and down, You NEED a zone system. Two separate heaters would be even better. The reason he's telling you to keep the fan running is to keep the air moving. If it wasn't the temperature variation would be even greater.
It was a penny wise pound foolish decision not to zone. A temperature variation of 3 to 4 degrees is considered a LOT!

 

[justfishing]

What energy effiency level was the home buily too. How well was it insulated but more importantly how well was it air sealed. A very tight and well insualted home will have a much lower level of heat stratification Then there isthe stack effect. Warm air is boyount and rises. This increases air leakage with the air leaking out the top and the cold air being pulled in from the lowest leaks. You symptons could be the sign of consctruction defects or the builder building to a low energy efficiency standard.

Running the blower 24/7 is trying to cover up the problem. I am not a fan of run a blower 24/7

Do you have duct work in the attic?

 

[brewchief]

Since the report lists the furnace as 92% I bet it's single stage and doesn't have a variable speed motor, you can try running the blower all the time but your electric bill will rise as a result.

I would wager that because of the energy report a heat load calc was done and the furnace was sized reasonably close.

Without zoning I doubt you will get rid of that large of temp variation.

Expect to spend more then the 4k option price to fix it.

Problems like this are what makes me glad we got away from new construction, homeowners are too cheap to spend a bit more to upgrade a mechanical system that will be there the life of there home but will gladly spend the money making the kitchen or bathrooms fancier.

 

[Teken]

If the builder is on side. Just get them to push the vendor to make the corrections. All of this guessing and band aid of leaving the fan running 24/7 is for retards.

Follow the suggestions from the other members, even better go out of your way and bring in two independent HVAC guys and have them review, investigate, than document the root cause of this temperature variation.

This, is all the proof you need. Spend the time and money doing this, will end all this bull **** in one fell swoop.

Teken . . .

 

[Dragster Racer]

So why do some homes (like mine) not have the upstairs vs downstairs variation problem? Our hvac guy was pretty sharp about cold air returns, and explained what he was doing and why. Our great room is open to the upstairs loft, and as long as the fireplace isn't going, all parts are comfortable. I think some would say that doing a dual zone is actually just another way of avoiding correctly planning out a system.

 

[HVAC Phil]

So why do some homes (like mine) not have the upstairs vs downstairs variation problem? Our hvac guy was pretty sharp about cold air returns, and explained what he was doing and why. Our great room is open to the upstairs loft, and as long as the fireplace isn't going, all parts are comfortable. I think some would say that doing a dual zone is actually just another way of avoiding correctly planning out a system.

Exactly! I never have problems heating 2 story homes. And you are right, having a zone system covers up the inability to properly design a system. As far as cold air returns go, you can never have to many. I often see other contractors that have more heat runs than the system can fill, but 1/2 the returns actually needed.

 

[JimL]

Exactly! I never have problems heating 2 story homes. And you are right, having a zone system covers up the inability to properly design a system. As far as cold air returns go, you can never have to many. I often see other contractors that have more heat runs than the system can fill, but 1/2 the returns actually needed.

Seems like every other house we go to has inadequate return.

We zone every house we do that is more than 1 level. If the home owner doesn't want to zone it then we don't do the job. Not going to put in a system that someone won't be happy with. I have never seen a house that had a single system that was feeding 2 levels keep each level the exact same temperature.

 

[danski0224]

what do you guys think?

Ductwork is messed up: first choice.

Building envelope problems: second choice.

Both: Likely.

The motor in your furnace is likely rated "continuous duty, air over". Running it all the time will not hurt it, but if the amp draw is out of spec, that will hurt it.

Good luck. Way too many possibilities to guess at. It would take some measurement and diagnostics to determine the problem. Anything else is just guessing.

 

[Chaz]

I understand that some two story homes heat more evenly than others. Stairwell placement has a lot to do with how the chimney effect works in each situation. I agree that you can't control the heating effectively without zoning.
I love that I can contol the temp in each area of the home and even keep the heat in the guest area of the home at 50 degrees when we have no visitors.

 

[steve308]

Just my .02 as it applies to running the fan full time. I called in a HVAC guy to review my lack of heat/cool in an addition with a vaulted ceiling. He ran the air volume test etc and he recommend I run the fan "full time" as the continous air flow would allow the HVAC when it did kick on to simply heat or cool more effectively the already circulation air. He said if I did not feel the difference he would gladly add a mini split to the addition. I've not had to install any additional HVAC since running the fan but I do have to change the filter more often which is much cheaper!