What are you heating with? I might have missed it. Propane or natural? Propane is kinda expensive these days and you can heat with strip heats almost as efficiently depending on where you are. I'm at the other end of the spectrum. I'm in Texas. It was 92 today. You need to look at the amount of insulation in your home as well as sealing it up as best as you can. No amount of efficient hvac can lower an energy bill as having your house insulated. Big bang for you buck IMO.
I like DIY'ers. They pay better to fix.
Some Talk, Some Do
Energy efficient and economical to operate are not synonyms
Here I sit several days later and have a cooling heat pump that runs all of the time i first stage kicking into 2nd stage periodically.
This morning it was off and about 68F and the thermostat was set for 75F. When the temp rose it began to cycle on and off in first stage. When the temp rose, it is now 82F, the heat pump stays running in first stage bumping up to second stage periodically.
Is this normal.
The jumpers on the furnace control board for the fan are set to
Adjust - "A"
Cool - "Hi"
Delay - "A"
Is this right?
The installer said he changed the Y2 Lock jumper to "Off".
House is nice and cool though!
They are suppose to run in first stage mostly. And for long periods of time.
With occasional periods of going to second stage and back to first stage on warmer days.
As it gets hotter out, it will stat n second stage longer and longer.
Sounds like the system is sized right. In your climate, I'd expect 1st stage to be running almost continously around 85F and the 2nd stage should be almsot 100% around 90-95F... if it was sized right. Solar heat gain is hte wild card here. The sun is most direct over the next 6 weeks, so in hte afternoon, you might even find it struggling a little to maintain temp in early afternnon if it gets into the mid 90's on a clear sunny day.
Originally Posted by Heetpump
Glad your system is working better.
As for winter efficiency, I'd take the costs of each fuel source and find the performanec data for your heat pump and determine the economical balance point. it's possibly that with low gas prices and hig helectric rates, that the point where both fuel sources are hte same cost, is higher than the thermal balance point where the heat pump runs out of capacity. On my system for example, it can maintain temp down to almost 25F, but the economical balance point is around 35-40F depending on the outdoor dewpoint (frequency of defrost cycles).
Another question. I have done some reading on this forum regarding return air. I measured my return air duct and found it to be 22"x10" which drops down and hooks into the side of the furnace. The filter is slid in between the duct and furnace and is a 14x20x1 Filtrete filter. It seems to me that this is on the small side based on what I read in this thread:
And its a Filtrete.
Put in a statandard air filter, and yu get more air flow.
So that means the return air ducting is the right size?
Originally Posted by beenthere
I am not able to find a standard filter that small. Filtrete is the only one available locally.
10 x 22 is ok for 3 tons.
That it comes down right beside the furnace, isn't the greatest for air flow.
14x20 is a common size down here.
The return cut out on that furnace is basically 14x24. So they are 4" shy on horizontal.
That filter is too restrictive.
The 3.5-ton with a max airflow of 1575-CFM would like a 18" Supply main, & Main Return duct system of 380 to 400-sq.ins., a 20x20 or, at least a 22" round metal duct, with Turning Vanes, in both Supplies & Returns, if possible, in any 90 turns.
This is taken from the previous mentioned thread. I have 220 sq. in. That seems a little shy of what this claims to be the minimum.
Why is this thread saying 3.5 ton needs 380 min. where a 3 ton is ok with 220?
Excuse my lack of knowledge but I think I am being taken to the cleaners.
I changed the filter to a cheapo filter (I found one in an obscure supply place) and it seems to flow freer.
Your 3 ton, at 1200CFM through a 10X20 duct is a velocity of 864FPM. Thats fine for a vertical return drop.
The other thread, is talking about return air filter grilles. And or return grilles.
A 20X10(if it exist)filter grille would be good for about 320CFM. And at a velocity of about 288FPM.
Grilles and ducts are 2 different things. And can not be figured/sized the same way.
For the record. A 10X28 return drop would have a velocity of 872FPM moving 1575CFM.
If, you are having a 4 or 5" media air filter installed at the furnace(or electronic).
Then you would want to transition to a larger duct. To slow the air down.
So, are you talking about just a return drop duct. Or about sizing for a media air filter?
Sometimes if you read too many things. Its easy to be confused about which thing/article was talking about what.
I am referring only to the size of the duct returning to the furnace. I read your response as it is sufficient.
Originally Posted by beenthere
What do you mean by "media filter"?
Yes, I have read too much with too little knowledge and have become confused. I am now starting to understand.
I have replaced the Filtrete filter with a cheap and nasty $1.39 filter. My concern with this is will this not accelerate the dirtying of the indoor coil? How ofter should it be cleaned using cheapo filters?
For the record it is 96F outside and the house is holding at 75F nicely. It seems that at about 4:00 PM second stage was the only option and is still running in second stage as I write this at 6:00 PM. The pump started at about 11:00 AM and cycled on and off first stage until 12:30 PM then went to constant first stage. It kicked up to second stage/first stage at about 2:300 PM.
Hopefully this is correct.
I will wait for the electrical bill and see if it was worth the install. The heating season cost me more money than my 1978 Lennox 120,000 BTU gas furnace.
Media air filters are less restrictive then those 1" filtretes.
And provide better filtration. Do a search on them on this site, and you'll find many threads about them.
Yes, your 10x20 is sufficient.