Forced air Questions

Irene_2

Now that I have learned alot about my steam boiler and had a new one put in, I am moving south. (South Carolina)I am looking at a house (20 years old) to purchase and it has central air and I am assuming some sort of hot air. The compressor says Goodman, Model CPKJ60-13. Anyone ever heard of this? What is the tonage? How do I find out. From what I have been told the air handler is pretty old and will most likely have to be replaced. What is a good brand of air handler? The house is about 2600 square feet. Like a tree house, seven different levels. Thanks

clammy

goodman

that's a 5 ton unit as for goodman i'v3e worked on them and i'm not to keen on them any unit that comes with a 250.dollar compressor change out allance just doesn't make me sleep to well espically when there's a big orange tag right on the outdoor unitsaying that and if the air handler is 20 years plus and you plan on living there a while have your indoor unit and out door unit changed to a higher seer units that are complatable or matched i usally just start a new line set fuseable dis connects and seperate returns for the bedroom gives greater overall system operation and evener temps thoughout your home good luck

Irene_2

What?

I'm not sure I understand the answer. What is a "250 dollar compressor change out allance" I have been told the compressor is about 3-4 years old but no idea about the age of the air handler. A neighbor told me they have a 3.5 ton compressor. What does tonage actually mean?
Thanks

Mark Hunt

Tons of cooling


AC systems are rated in "Tons of cooling".

One ton will remove 12,000 btu's of heat/hour from your home. The 5 ton unit you have will remove 60,000 btu's/hr.

Goodman was/is Janitrol. Commonly referred to as "contractor grade" equipment.

In that part of the country you would be doing yourself a favor by looking into a "S.E.E.R" upgrade. I would recommend 13 S.E.E.R or better.

I personally like Trane equipment.

Mark H

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Irene_2

heating

There doesn't seem to be a separate furnace. Are there heating coils in the air handler? Is that how they make heat in South Carolina. I am already missing my steam boiler!

Mark Hunt

Probably a


heat pump.

In the colder months the heat pump will extract BTU's from the air. YES, there are BTU's even when it's 5 degrees outside. There are probably electric resistance coils in the air handler for the times when the heat pump can't keep up.

You'll miss your steam system for sure, but I bet you won't miss 30" snow accumulations!

Again, you should DEFINATELY consider a S.E.E.R upgrade.

Mark H

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Irene_2

heating

It does sound like the system needs to be replaced. Is it better to have a heat pump or a furnace? Is there a difference? Is a heat pump different than the Goodman thing that is there?

scrook_2

combo heat pump / AC unit

it'll heat at ~50,000 BTU/hr at 47°F and ~30,000 BTU/hr at 17°F (In SC you're probably looking at design temps of +20°F to +25°F depending on the location) as a heat pump.

Basicly, in the winter you air condition the outdoors and dump the heat into the house, in the summer it's reversed: you air condition the house (at about SEER 11.3 to 12 depending on the particular model) and dump the heat outside. This is a common arrangement in warmer climates.

You may also have electric resistance heat as a backup for when it's real cold, depending on whether the heat loss of the structure is higher than the output of the heatpump at design temperature conditions.

Mark Hunt

I would


give the heat pump a chance. You will be doing more cooling than heating (hope hope) and the outdoor temps will never be what they are here in New York (hope hope) so the heat pump is not a bad idea there.

I would look at the SEER or Seasonal Energy Efficiency Rating of the equipment that is existing. 13 SEER would be the MINIMUM I would look for.

Mark H

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Duncan_9

250 dollar compressor changeout allance

I think he meant $250.00 compressor changeout allowance.

In other words if the compressor fails while under warranty, the manufacturer will only pay the contractor $250.00 to change out the old compressor for a new one. Not a good deal for the amount of work involved, and it might not be the only work that needs to be done.

When a bad compressor burns up, it could contaminate the entire refrigeration piping system with sludge and acidic compounds, parts including the cooling coils and refrigerant metering valve. This is a lot of work to clean up.

Starting new line set means he would replace the copper refrigerant lines from the compressor to the air handler.

Fuseable disconnects means he would install an outdoor electrical service disconnect box with fuses - a good idea and required building code in most plaaces.

Separate returns in the bedrooms: Returns are air registers which return cooler room air to the furnace. Warm air comes into a room through a supply register, cold air goes out through a return register, back to the furnace. Also a good idea. Most tract homes have a single return register centrally located in a hallway, for example. If there's no return register in a room, and the door closes tightly, getting heat in that room is like trying to blow air into a closed box - not too efficient.

Many central air system have both furnace and cooling coils in the same air handler. If this is the case, there would be a burner compartment in the ar handler, as well as a black iron pipe gas line to it.

Red flag *** A big concern in a seven level house is air delivery. It can be tricky getting ductwork into all those different levels. If the ductwork is too twisty and turny and long as it winds its way to that way-out-of-the-way seventh level of the house, there might not be enough pressure left to deliver enough hot air to heat the room. This ductwork resistance to airflow is called static pressure. ***

Your blower will need to overcome this resistance to flow (static pressure), and still deliver enough cubic feet per minute of air to heat the room.

The tonnage, or cooling capacity of your unit will depend a lot on shading and insulation levels in the home. The more it bakes in the sun and the less insulation it has, the greater the heat gain (which is actually the cooling load). You need enough cooling capacity (tonnage) to meet the load.

A ton of cooling is (like horsepower) an archaic term still used today. It's the amount of heat required to melt a ton of ice in (I think) 24 hours. Yeah, that's it... a horse and wagon delivering ice to an icebox.

Blowers are usually matched to the cooling coils. To picture a cooling coil, imagine a couple car radiators with cold water (or refrigerant) running through them stuck in a duct. The blower has to be strong enough to blow through the air side of the coils AND overcome the static pressure of the ductwork.

So a 3 ton cooling coil might typically be matched with a 3 ton blower. Kind of a misnomer actually, rating a blower in tons.

Suppose a home has a 3 ton cooling load but the ductwork is really restrictive to airflow. You may need to upsize the blower only using a blower designed for a 5 ton unit. It'd be loosely called a 3 ton coil with a 5 ton blower. But if the blower is too big, small leaky ductwork starts sounding like a big harmonica.

This is probably way too much technical information. There's gotta be a website somewhere with pictures and all that describe this much more clearly. You just want to know what kind of system you have and if it will work.

What you really want to know is: does the system heat and cool the rooms comfortably? I guess simply asking the former owner if all the rooms are comfortable may not get you the quality of answer you need.

How do the heating and cooling bills of this home compare to similar homes in the neighborhood? If there are any similar homes.

scrook_2

Goodman...

is just a brand name. Think of Ford vs Chevy vs Dodge).

AC / Heatpump vs. A/C + furnace is like a gasoline burning car vs. electric car -- except electric cars are rather uncommon -- both will get you where you are going though.

The heat pump is just an air conditioner running in reverse (they switch some valves) so it heats the indoors. A furnace burns fuel to heat a metal heat exchanger which heats the air as it is blown over the other side of it
Do you have natural gas at the house (or at least in the street) already? If no, than the heat pump may be the best/simplest option. If yes, well, it depends! You are fairly far south, so it doesn't get too cold in winter so a heat pump may be best anyway, but it's hard to say.

Best to talk to some local heating/air conditioning contractors, they should know what makes the most sense in the region.

Irene_2

heat/AC

Okay things are starting to become a little clearer now. Looks like I need to replace both the Heat pump compressor thing as well as the air handler. They should be at least a 13 SEER. Any comments on Brands and what else should I be aware of? Things to avoid...
Irene

jim lockard

Amer.Standard

IS number one based on consumer reports mag. Best WishesJ.Lockard