Ok. So the house is close to 40 years old and we still have the original Electric Heating system, no Heat pump. First, the house was built on a slab, no basement. It works somewhat fine Except!!


Why do some of the ducts produce strong blowing heat coming out and others barely any? Let me explain. We have closed some vents completly on the downstairs and/or upstairs levels and same thing, some in the kitchen area produce a strong amount of blown heat coming out and others not much. Of course, you cannot tear up the slab and redesign the heating duct pattern. Some of the ducts producing the most heat are farther away from the actual furnance that is located in the middle of the house utility room. The actual electric furnace is fine blowing out warm air.

Was it an original poor design with bends in them? What if anything can be done? Just some questions and looking for ideas. A heating serviceman would be a total waste of time as I just don't seeing them solving this problem.

I doubt the ducts go into the slab. Since you vaguely indicate that the house is multi-level, I suspect there is a central shaft for the duct work to go up. In between the first and second floor are likely runs from that shaft to the exterior walls for vents for the second and third floor. At 40 years old, you don't have insulation on your ducts so the longer the run or the closer to unheated spaces, the less heat will make to the register. The uninsulated ducts in my crawlspace used to blow 75F air when the heat was running.

As for a heating pattern, close all second and third floor vents. Heat rises.

The bottom ducts are definitely built in the slab and yes the upper ducts run up thru the exterior wall and thus make it to the upper level. Sorry, yes the house is two levels as I stated downstairs and upstairs ducts.

Correct: "I suspect there is a central shaft for the duct work to go up".

I just think the bends it makes just on the first floor, heat is escaping on the first floor under the slab. I did like your response and appreciate your comments.

One comment: Electric furnances running, when I watch the DomPower meter outside are like cash registers!

How long have you lived there?
How can a duct be in the slab? That makes no sense.
I would switch to gas if available. Electric heat is a joke and heat pumps don't work here.

Ducts in slabs seem very rare in this area. Galvanized ducts in a slab are just a failure waiting to happen. Given the damp in the area, I can't imagine how they have rusted away. I doubt they are insulated and a fair amount of energy goes into heating the slab.

As for bends in ductwork, 90 sharp bends are common. Yes, you will get some losses associated with that, but the system is usually designed to accommodate those losses with more air flow.

Electric (coil) heat is not very efficient.

It was common here in the houses built here in Brookfield subdivision 40 year ago, smae with Greenbriar.
The ones on the first floor are 100% in the slab, not in the wall.

As one other person said, with the 90% bend I actually think that is where the heat loss is happening. What a poor design building them in a cold slab.
I also think that some of the duct work going from the 1st to 2nd floor, thru exterior walls, was not lined up in the joints of the duct work.

An advantage to a house built on a slab is that it is much cooler in the hot months of the summer as the A/C has to be used less.

Homeowner here Wrote:
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> Electric heat
> is a joke and heat pumps don't work here.

I disagree. For a smaller home in this area heat pumps are great and inexpensive to operate. The newer ones (2009 and newer) are very efficient and keeps my house 2500 sq ft nice and comfy. The only time the back up heat kicks on is in the coldest of cold, like under 20 outside. I have a Rheem installed 2011.

pEJPT Wrote:
-------------------------------------------------------
> Homeowner here Wrote:
> --------------------------------------------------
> -----
> > Electric heat
> > is a joke and heat pumps don't work here.
>
> I disagree. For a smaller home in this area heat
> pumps are great and inexpensive to operate. The
> newer ones (2009 and newer) are very efficient and
> keeps my house 2500 sq ft nice and comfy. The only
> time the back up heat kicks on is in the coldest
> of cold, like under 20 outside. I have a Rheem
> installed 2011.


You are both right in a way. Heat pumps are perfect for this climate IF you have a properly insulated home. Properly insulated homes are generally ones built in the last 15 years or so.
If you live in a place like Brookside or Kings park or Canterbury woods or sleepy hollow or Pimit Hills chances are you have a poorly insulated house.
When those homes were built the thing was to put a big 100,000 btu furnace in a 1200 sq/ft home and just let it rip and waste the hell out of some energy. A 1200 sq/ft house built today can likely be heated with half the energy and can easily be heated with a heat pump that blows gas furnaces out of the water on efficiency.
I have replaced hundreds of gas furnaces in these older neighborhoods and recommended against a heat pump because of the insulation issue. You can put all the insulation you want in the attic but it will help only a little.

Hey Energy Guy, great response by you. Yes, my furnance is a heat hog.
Luckily a few years ago I found some corrided split wires, thru vibration I imagine, and was able to fix them myself. Yes, I was very careful with power off.
Made a big difference in the warm air being produced by the furnace.

1970 houses...yes, very poorly insulated. I did both attics on the 2 story, one near the roof and the other over the kitchen.

I still use some space heaters in rooms we stay in my to heat them up.

The wires were at the elements. Pretty easy fix.

Given the other things you've done, I assume you've checked for/settings of dampers in the duct work itself? Dampers are air valves inside the ducting that are used to balance the amount of air running thorough different branches of the duct work. Most houses have manual dampers that get set once and forgotten. Some newer/larger places have automatic ones that can be remotely managed & driven off wifi thermostats. If the house doesn't have any or if they are poorly positioned or poorly set, ...

Also, I've never had mine done, but there are duct cleaner guys. No idea if it actually makes any difference unless they are really bad (aka a house full of kids who had fun with tennis balls some weekend).


JustaHomeOwner Wrote:
-------------------------------------------------------
> Ok. So the house is close to 40 years old and we
> still have the original Electric Heating system,
> no Heat pump. First, the house was built on a
> slab, no basement. It works somewhat fine
> Except!!
>
>
> Why do some of the ducts produce strong blowing
> heat coming out and others barely any? Let me
> explain. We have closed some vents completly on
> the downstairs and/or upstairs levels and same
> thing, some in the kitchen area produce a strong
> amount of blown heat coming out and others not
> much. Of course, you cannot tear up the slab and
> redesign the heating duct pattern. Some of the
> ducts producing the most heat are farther away
> from the actual furnance that is located in the
> middle of the house utility room. The actual
> electric furnace is fine blowing out warm air.
>
> Was it an original poor design with bends in them?
> What if anything can be done? Just some questions
> and looking for ideas. A heating serviceman would
> be a total waste of time as I just don't seeing
> them solving this problem.

JustaHomeOwner Wrote:
-------------------------------------------------------
> Hey Energy Guy, great response by you. Yes, my
> furnance is a heat hog.
> Luckily a few years ago I found some corrided
> split wires, thru vibration I imagine, and was
> able to fix them myself. Yes, I was very careful
> with power off.
> Made a big difference in the warm air being
> produced by the furnace.
>
> 1970 houses...yes, very poorly insulated. I did
> both attics on the 2 story, one near the roof and
> the other over the kitchen.
>
> I still use some space heaters in rooms we stay in
> my to heat them up.


I remember the type of ductwork that goes under the slab and even installed some as a young kid starting out in the trade, it was called transite. Turns out the mastic we used for sealing it was chock full of asbestos which is not dangerous after it has dried and hardened but is probably going to kill me soon.
Electric space heaters are no more or less efficient than your electric furnace but you have to be very careful with them. Some nut-job on the off topic forum has a whole thread about space heaters.
You might want to look at the possibility of getting a couple Mr Slim heat pumps from Mitsubishi. They are ductless split heat pumps that mount high on the wall and just heat or cool one room. I have two Mr Slims in my home and love them.

There have been a lot of changes to heating systems over the last 40 years. Interest rates are at historic lows. This might be an opportune time to do a little research and see if a new HVAC system is in your future.

WestfieldDad Wrote:
-------------------------------------------------------
> Given the other things you've done, I assume
> you've checked for/settings of dampers in the duct
> work itself? Dampers are air valves inside the
> ducting that are used to balance the amount of air
> running thorough different branches of the duct
> work.
>
>

I have dampers that can be adjusted manually. Every year in the Spring I set them to blow most of the cool air to the second floor. In the Fall I reset them to blow most of the warm air to the first floor. Takes about 5 minutes.

That's exactly what I've done as you described above. Closed upper dampers during the winter. Use a nice 1500W HEATER in the bedroom for sleeping AT NIGHT and that works fine.

Somebody finally agreed with me that I do have duct work under the slab!

Am I reading correctly that those MrSLIM Heat Pumps are over 1K?

A couple other possibilities/hacks -

1) Depending on placement of return registers, whether doors are kept closed, etc. there are return airway ducts that fit in doors/in walls to allow air to move freely to the returns.
2) Inline duct fans for the worst spots.

A couple of the ducts in kitchen on the 1st floor, the heat/air comes out really strong. The ducts over in the other side living room not as strong.
When those elements had a couple of wires that were burnt out or frayed off, probably due to vibration (correct?), the heat was horrible. So when I fixed them it is working much better. Actually, lucky I found them.

I've cleaned all I can clean in ducts, return vents, etc. so for this 40 year old unit which we barely run it will have to do. Don't have the bucks to throw into a completely new unit?

On that note, YouTube is the greatest tool of this century....I've fixed so much household stuff just by watching YouTube.
Clothes dryer element replaced, Carb rebuild in lawnmower, refrigerator coil cleaning when I thought we needed a new one, replaced gears inside a garage door opener and replaced chain, and more.
YouTube is knowledge - nothing is better.

Hey OP, have you ever tried leaving the fan in your furnace in the "on" position? I lived in a townhouse when I was younger that had airflow problems and I started leaving the fan on all the time. I liked the results so much that I ran the fan from 1988 till 2000, 24 hours a day 365 days a year. The motor had to be replaced after about 7 years of continuous use. It made the house comfortable and actually saved me money because I was able to keep the heating set-point lower and the cooling set-point higher.

Hey Fred, Thanks. Let me give that some thought.

Electric furnaces are 100% efficient but a decent heat pump is at least 300% efficient.

Well, you could position a small furnace in two places in the house and run ducting thru the attic and in between floors. It's costly and a lot of retrofitting and renovation, but at some point, the slab ducting is just unrealistic.

Or maybe Mitsubishi mini-split ductless systems.

Dampers, check them.

Fairfax Fred Wrote:
-------------------------------------------------------
> Hey OP, have you ever tried leaving the fan in
> your furnace in the "on" position? I lived in a
> townhouse when I was younger that had airflow
> problems and I started leaving the fan on all the
> time. I liked the results so much that I ran the
> fan from 1988 till 2000, 24 hours a day 365 days a
> year. The motor had to be replaced after about 7
> years of continuous use. It made the house
> comfortable and actually saved me money because I
> was able to keep the heating set-point lower and
> the cooling set-point higher.


Also, if the air is too dry in the winter, it feels colder. Adding a whole house humidifier allows people to turn the heat down a little bit and still feel comfortable.

You sound like a fucking foreigner who has no idea what America was like in the 1970's

#1 it was ahead of your county anyway

#2 it included people starving in the streets*

there was not time to custom design central air systems per home, that would have been a sin. your lucky you even have central air: there are people living in boxes

YOUR WEARING YOUR CHRISTMAS SWEATER ANYWAY - so don't complain - many in manassas are cutting wood and using a wood stove no "easy electricity"

most everyone was white and attending church in fairfax

that was fairfax in the 70's

and anyway it probably was designed "adequately" - your probably using it wrong

the kitchen is warm from cooking anyhow

the family stays in one room - they aren't there during the day they are at work

the family in the room at night keeps the well heated room warm

the thermostat is at 68 degrees like president carter asked

and you put on your long jons when your in your room away from the family which ONLY occurs at bed time

DO YOU UNDERSTAND THE ROUTINE NOW?

oh - and if i'm out of work i don't use electric heat unless it's 10 below outside - i had a wood stove

Just a thought.... Wrote:
-------------------------------------------------------
> Fairfax Fred Wrote:
> --------------------------------------------------
> -----
> > Hey OP, have you ever tried leaving the fan in
> > your furnace in the "on" position? I lived in a
> > townhouse when I was younger that had airflow
> > problems and I started leaving the fan on all
> the
> > time. I liked the results so much that I ran
> the
> > fan from 1988 till 2000, 24 hours a day 365 days
> a
> > year. The motor had to be replaced after about
> 7
> > years of continuous use. It made the house
> > comfortable and actually saved me money because
> I
> > was able to keep the heating set-point lower
> and
> > the cooling set-point higher.
>
>
> Also, if the air is too dry in the winter, it
> feels colder. Adding a whole house humidifier
> allows people to turn the heat down a little bit
> and still feel comfortable.

Whole house humidifiers waste a shitload of water and put mold in your house.

Call Michael n sons u cheeep bastard.
Amortize the cost of a new system vs ur monthly savings and how uncomfortable you are.

Michael n his sons Wrote:
-------------------------------------------------------
> Call Michael n sons u cheeep bastard.
> Amortize the cost of a new system vs ur monthly
> savings and how uncomfortable you are.

U tryin ta respond to a 4 year old post. That mofo has probably moved to Wes Virginia by now an is heatin with wood.

bone dry Wrote:
-------------------------------------------------------
> Just a thought.... Wrote:
> --------------------------------------------------
> -----
> > Fairfax Fred Wrote:
> >
> --------------------------------------------------
>
> > -----
> > > Hey OP, have you ever tried leaving the fan
> in
> > > your furnace in the "on" position? I lived in
> a
> > > townhouse when I was younger that had airflow
> > > problems and I started leaving the fan on all
> > the
> > > time. I liked the results so much that I ran
> > the
> > > fan from 1988 till 2000, 24 hours a day 365
> days
> > a
> > > year. The motor had to be replaced after
> about
> > 7
> > > years of continuous use. It made the house
> > > comfortable and actually saved me money
> because
> > I
> > > was able to keep the heating set-point lower
> > and
> > > the cooling set-point higher.
> >
> >
> > Also, if the air is too dry in the winter, it
> > feels colder. Adding a whole house humidifier
> > allows people to turn the heat down a little
> bit
> > and still feel comfortable.
>
> Whole house humidifiers waste a shitload of water
> and put mold in your house.


Only if you don't know WTF you're doing.

How the hell do you hold down a job? Oh, you don't.

BYVWE Wrote:
-------------------------------------------------------
> bone dry Wrote:
>
> Only if you don't know WTF you're doing.
>
> How the hell do you hold down a job? Oh, you
> don't.


Even with the humidifier on in the winter, it's still way more humid in the summer after a rain storm. Dude is retarded.