jkcole18

I am not a hvac man Im a media blaster my question is----
My home is around 2000 sq ft. and my current unit is not cutting it, so a local hvac contractor sold me a 5 ton air handler and a 4 ton heat pump, something does not sound right, it is scheduled to be installed here in about 2 weeks.
Is this going to work?
Im just lookin for more comfort and power bills to go down
OH YEA current unit in home is over 25 yrs old and not sear rated
please help

Anti-wingnut

With the exception of increases in efficiency, lower bills and more comfort are mutually exclusive. Are you not comfortable because the cooling cycle is no keeping you cool enough? Not warm enough? A modern and properly sized unit will make the most use of its electrical usage. Did your HVAC guy do heat calc's? They are getting few and far between now-a-days. How did he size your unit, that is the crux.

beenthere

Not uncommon for the indoor coil to be a ½ to 1 ton larger rating then the outdoor unit.

As above, did they do a load calc?

What size was your old unit?

Many times. A system doesn't cool the house the way the owner wants, for reasons other then its size.

Since you have an older house.
Have you tried to reduce your fresh air infitration rate.
Easy to do. Caulk around all windows. Install seals on all receps and switches on outside walls.
If any of your electrical wiring runs to the attic from switches or receps on the inside walls. Seal them also.
Replace/repair all door seals.
If you have any recessed ceiling lights. See if they can have an insulated box put over them in the attic. To prevent conditioned air from being drawn into the attic.

These are things that will do more for reducing your cooling bill then a new A/C.

The average A/C, barely delivers 80% of its rating. Due to poor duct work.

jkcole18

he did no kinda figuring just said it would work and had a great prce on it (1500.00 complete and new). Our heating bill it great less than 600.00 per winter its gas(will miss that) and will be switching to all electric although we are on a pad and the floor never really warms up and we want to get rid of the carpet and go with hardwood floors, its the cooling we are having problems with only cool early in the mornings and in the evenings otherwise the inside temp flirts with 80+ all summer and 400.00+ ea. month. current unit is to old for sear numbers but tech guessed it around 2 or 2.5 tons bare min. for 1980 he said also I have insulated solid duct work

beenthere

He's selling and installing it for 1500 bucks????

If your current system is 2.5 tons.
Your duct work will NOT handle enough air for 4 tons. And will be very loud.

Get some other estimates. Before you end up with a white elephant.
And paying more to get another unit.

PS: what is your gas rate delivered including all taxes and delivery fee's.
And what is your electric rate delivered, including all taxes and transmition fee's.

flashheatingand

Just from reading what you are writing, if the unit was only 2.5 tons and the house never dropped below 80, you are likely undersized. You can spend $ insulating the envelope, or $ buying a larger sized unit as scheduled. I lived in the south, for a few years. It gets humid and there are lots of days where a heat pump is ideal. Obviously, a heat load calculation should be performed. $1,500 installed is awfully an awfully good deal. There are load calculation programs on the internet. You need to do this on your own that way you will know if you are getting too much unit.

On the surface it sounds killer, but you probably want to make sure the money is well spent. Not squandered. If you have a bad vibe about the guy don't do business with him. You want to do buisness with someone you have confidense. A decent amount of money is going to be spent and you want to know that you can call him if something goes amiss. Good luck. Also, does this include electrical & heat strip kit? .

Chris Johnson

I'm not an HVAC guy, but insulation is a key component to a good efficient system. With your description of extremely hot in the house during the day I would say check the attic insulation and air flow vents.

This may very well be a majority of your problem.

__________________
Chris

jkcole18

I have to do the electric and buy the heat strips, but I kinda know the guy and he lives not 2 miles from me and said he would back it up he had just ordered it for another customer last year job didnt happen and then he needed some cash a few weeks ago so I bought it cheap, my father-n-law who I dont get along with told me it would "short cycle" and that would be bad me I dont know.I just call the guy about the duct work size and he said if any problems we could work it out at cost.
please help and what is short cycle and what about it?

Chris Johnson

Short cycling is the unit kicks on and kicks off really soon and does this repetively too often causing undue wear and tear on the equipment, the system does not get up to full running capacity. You would rather the unit kick on, run for a certain period of time at it's regular speed and then shut down.

Picture this, drive your car around the city only and you burn more fuel and parts wear out faster, now use the same car and do solely highway driving, everything is consistant for a longer period of time, brakes last longer, speed is consistant for better fuel milage, etc.

I think your father in law is correct.

__________________
Chris

jkcole18

the attic has roughly 8 to 10 inches blown insulation

naptown CR

The big concern during the cooling season is dehumidification. To get the most dehumidification you want the unit to run longer so the air cycles through the coil more times removing moisture. If you over size a unit the house will cool very rapidly however the moisture will not be removed. this will feel like a cold damp meat locker if you will. On top pf that it is not good for the equipment.

jkcole18

thank you all for all the great info I guess I now have a new 5 ton air handler and a 4 ton heat pump for sale and im in the market for an new system

flashheatingand

If you bought the unit already, unless you can sell it right away (an installer has had it for over a year and couldn't sell it), you might as well put it to use. Nobody here knows what your heat/cool load is, you were just told of the possible results of oversized equipment. Heck, it's possible, the duct work is sized to handle the larger unit. There are ways to make it work alright. I lived in Ms. for a couple of years it gets awful, there are days when that thing will perform like a champ.

The insulating thing is correct, but you might as well make lemons over spilled milk.

beenthere

How many homes have you been in. That had a 2.5 ton system. That the duct work was big enough for a 4 ton heat pump.

72chevy4x4

I've remodeled enough 60's era houses to find absolutely nothing (insulation) in the walls. If this is the case with you, consider blown insulation in the walls (get a 'reputable' installer who knows his job), tyvek (under new siding) and new windows/doors. You could get a blower door test done on the house to check for air leakeage. Also add some insulation in the attic and ensure airflow can come up the soffit and out the peak-install ridge vent if necessary. If the hot air gets into the attic and doesn't escape, its like your living area is located next to an oven!

flashheatingand

I can't say that many, but There have been several instances when the furnace was bigger than the duct work. It's not a perfect world. Dude committed $1,500 and his local guy suggested this bigger unit. It may be loud, but there are things they can do to minimize the situation. Better yet, he will be comfortable on those God awful days.

I would suggest adding a couple of supplies, and add a return. Maybe a by-pass damper.

beenthere

Yea, he'll probably be nice and cool if his area hits 110°.

But he'll probably have to set his stat to 64 when its only 85° outside.

flashheatingand

Thats all good if this was done before the transaction. Economically, he is better off with the oversized unit versus insulation costs. It's not so bad to let the home "breathe" anyways.

As I recall, the weather down south doesn't get as bitter cold as it does in other areas.

Texahoma

Have him provide you with a ARI certification sheet that shows you have the correct match up. Ask him for the model numbers and the brand name.

flashheatingand

Thats something I do not necessarily "agree" on. Sure, there are more 85 degree days per year than say 100+. However, it is more critical that the system be able to handle 100+temps. The heat can be a killer. Both financially, and physically.


I haven't been in the South for years, so I don't know if 85 is worth turning on the a/c. Here, running the a/c when odt is below 90, is indulgent. Unless, of course you live in a tight home and leave all windows closed.... Another topic.