Heater / AC

[Greg Peterson]

Our NG heater is old, old, old.

After living through a ten days of above 100 degree's last summer, with a coupe at 109, and a few above 105, it was decided that central AC would need to be considered.

Anyway, any advice, opinions, suggestions or preferences would be greatly appreciated.

[Matt Meiser]

First suggestion: let people know where you live--things vary widely by region. :)

[Greg Peterson]

Good point.

Milwaukie, OR (Portland metro area)

[Don Jarvie]

You need to have someone come and look at your house and see how it is set up. If your house is on two floors it may be most cost effective in the long run to have a furnace for each floor.

For a system to work effectivly the returns should be on the same floor so it can pull out the hot air and blow in the cold. If your return is one 1 floor it can't pull enough hot air from the other to cool the other floor so the furnace has to work hard, like running all the time.

While the equipment can handle running all the time your wallet may not like the bill from the gas and electric usage.

Any other questions let me know.

[Jim Finn]

I am a former heating and A/C contractor: I suggest you call a few contractors in your area and pick their brains. Get some prices and ideas (as long as they are free).
I do know that in a humid area an A/C unit can be oversized so biggest is not always best. Not so critical in a dry area.

[Greg Peterson]

Our house is a small ranch, less than 1,500 sq. ft. House faces west and gets absolutely slammed by the sun.

In the Willamette valley our summers are generally pretty dry. Matter of fact, it's almost drought like. Humidity isn't generally an major issue. One of the biggest problems for our house is the lack of shade. It will be several years before the sugar maple gets large enough to provide meaningful shade.

Are there any brand preferences?

[Sean Troy]

When we lived in Arizona, it was recommended to use a 1 ton per 500 sq. feet. High seer values are more efficient and cost more but savings in utility bills can make up the difference. Seer 16-17 are pretty efficient.

[Jim Finn]

[... Humidity isn't generally an major issue. ....
Are there any brand preferences?[/QUOTE]
.............. humidity is about 11% here in west Texas summer. That is dry! A contractor can size a unit for you for your area. I like Carrier myself, but size and instalation are more important than brand.

[Bill Cunningham]

Look at a heat pump.. I'm in Southern Ontario, and Temp runs from +80 to 100 in summer, and -20 to +50 in winter. My heat pump works well down to -15 F before the furnace kicks in. If you further south than me, it may supply all your heating needs.. I have the one below coupled to a 3 stage High eff. furnace..

http://www.residential.carrier.com/products/acheatpumps/heatpumps/infinity.shtml

[Greg Peterson]

Did not think about a heat pump. Excellent idea. Our weather is generally pretty moderate. We do get some extremes but these are the exception.

[Brian Elfert]

I am assuming the NG heater is really a forced air furnace. If I am correct it would make sense to replace the furnace at the same time as adding A/C.

Any sort of rule of thumb like 1 ton of A/C per 500 square feet is just plain silly. A/C requirements can vary greatly based on region and age of the home along with the insulation levels of the home. My house is 2800 square feet, but I get along fine with 2 tons of A/C. This is because my house is 8 years old and well sealed and insulated. Older homes in the area have 3 to 4 tons of A/C for the same square footage.

A good HVAC company will do a manual J calculation on your house to properly size your air conditioner and furnace. You should show the door to any HVAC salesman who simply sizes by square footage.

[Lee Schierer]

Did not think about a heat pump. Excellent idea. Our weather is generally pretty moderate. We do get some extremes but these are the exception.

If you have the space for the wells or ground loop coils a geothermal heat pump will be much more efficient for both heating and cooling than a regular heat pump. We've heated our house with one for over 25 years and we upgraded to a newer unit 2 years ago to add A/C. We ran the A/C July August and September for the same KW's that we used the previous summer running fans and were more comfortable.