Heat Pump vs A/C: What's better in 130 degree sunlight?

[Carnivore]

I live on the top floor of a 4-story condo building and I'm thinking of replacing the gas furnace (located in loft) and the A/C unit (roof of building). Reason being is that they're both Goodman brand and they don't cool or heat sufficiently in extreme weather (90+ degrees in summer/30 degrees in winter). Another reason is that the furnace is so loud.

Anyway, with the A/C unit being on top of the roof, it gets very hot up there, up to 130 degrees on summer days (I'm located in the DC area).

Would a heat pump perform better in that environment or should I look for an A/C unit? I'm thinking of going with Carrier.

Thanks in advance for any feedback.

[gravity]

a h/p or a/c doesnt matter. i work in the dc area and the most common problems i see in the high rises are

1. the outdoor units are crammed next to each other with no air to breath
2. the units are not sized correctly
3. the ductwork in these places are horribly wrong.

im going to take a guess and say your main return duct or grille is right next to the furnace?

[gravity]

before replacing the equipment i would also recommend having a qualified tech come look at your system and make sure it is running up to par.

clean coils, proper refrigerant charge, proper airflow, correct filters...

its amazing how well a unit that a homeowner wants to get rid of because it has never worked right will actually work if properly tuned up.

[udarrell]

I live on the top floor of a 4-story condo building and I'm thinking of replacing the gas furnace (located in loft) and the A/C unit (roof of building). Reason being is that they're both Goodman brand and they don't cool or heat sufficiently in extreme weather (90+ degrees in summer/30 degrees in winter). Another reason is that the furnace is so loud.

Anyway, with the A/C unit being on top of the roof, it gets very hot up there, up to 130 degrees on summer days (I'm located in the DC area).

Would a heat pump perform better in that environment or should I look for an A/C unit? I'm thinking of going with Carrier.

Thanks in advance for any feedback.
There shouldn't be much difference between H.P. & A/C.

If the small liquid line is on or very near a hot roof it needs to be insulated or it could flash-vapor.

The condenser could be drawing excessively hot intake air reducing its capacity & efficiency.

[Carnivore]

a h/p or a/c doesnt matter. i work in the dc area and the most common problems i see in the high rises are

1. the outdoor units are crammed next to each other with no air to breath
2. the units are not sized correctly
3. the ductwork in these places are horribly wrong.

im going to take a guess and say your main return duct or grille is right next to the furnace?

1. You're correct, there's 6 units up there all next to each other with no air movement whatsoever.

2. I've always suspected this, which is why I was looking to replace it.

3. I've also suspected this and I've been thinking about getting the ducts looked at... possibly get them sealed if needed.

The grille is about 6 feet from the furnace. The grille is located at the top of the loft and runs horizontal to the furnace.

[Carnivore]

before replacing the equipment i would also recommend having a qualified tech come look at your system and make sure it is running up to par.

clean coils, proper refrigerant charge, proper airflow, correct filters...

its amazing how well a unit that a homeowner wants to get rid of because it has never worked right will actually work if properly tuned up.

Last summer they had to put more stuff in it (F-22?) which makes me think there's a leak somewhere, right? If it's properly sealed, it should never run out of that stuff, correct??

But I'll take you up on your recommendation to have them look at it... I need to get maintenance done on it anyway.

Thanks!

[gravity]

yes r-22. but more importantly we need to make sure your coils are clean and you have proper airflow before adjusting refrigerant charge. how old is your system?

[Carnivore]

yes r-22. but more importantly we need to make sure your coils are clean and you have proper airflow before adjusting refrigerant charge. how old is your system?

It was purchased about 5 or 6 years ago by the previous owner... I took ownership of this condo in '09.

When you say proper airflow, do you mean that the ducts aren't leaking and not dirty? Or to make sure that the furnace is big enough to move enough air through the ducts??

Thanks for your quick responses!

[gravity]

make sure ducts are sealed. which means.

1. your return is only pulling air in from the grille and not air coming in from attic space.

2. your supply is sealed and the only air coming out is at supply registers.

3. if you have a 2 ton unit, make sure your moving 2 tons of air thru supply and return

[gravity]

if the unit is only 5-6 years old you should get atleast another 5-6 years out of it

[Carnivore]

Ok great, thank you sir!!

[pstu]

It was purchased about 5 or 6 years ago by the previous owner... I took ownership of this condo in '09.

When you say proper airflow, do you mean that the ducts aren't leaking and not dirty? Or to make sure that the furnace is big enough to move enough air through the ducts??

Thanks for your quick responses!
Just a piece of the puzzle. Rather than thinking "the furnace is big enough to move air thru the ducts", try reversing your thought. It becomes "the ducts big enough to move all the furnace's air".

I am a homeowner not a pro, but have read again and again about ductwork that is too small for the airflow the machinery requires. Then somebody sells the homeowner a bigger furnace b/c everybody thinks if it isn't cooling well then it must be "undersized". A measurement of static pressure (most pros can do that) is one way to tell if the overall duct system is restrictive or not. I wish everybody would have this number for their system.

If you have a localized problem such as particular rooms not cooling or heating well, that requires digging deeper than static pressure. No substitute for a professional HVAC guy who thinks like a building scientist.

Best of luck -- Pstu

[GAC]

[QUOTE=udarrell;10396622]There shouldn't be much difference between H.P. & A/C.
QUOTE]

In cooling mode HP and A/C are essentially the same, but in the winter is where you might notice the difference. HPs cannot put out that blast of hot air like a furnace. The air will be warm, but not quite as hot as you are used to. Also, they are more efficient than gas, but you will probably need electric heat strips for backup when the outdoor temp goes below the balance point. Just food for thought....

All good suggestions here. Before making any changes, it's a good idea to get your unit clean and ducts sealed. Not sure if there's anything you can do about the crowded roof though.