Room AC Questions

[Jim McLaughlin]

Here in the Pacific NW we usually have no need for AC. Yet the older I get, the more the rare 100+ day affects me. We are going through a series of 3 or 4 of those days now.

So I'm thinking about the room AC option. I'm not intending to stay in this house more than another 8 - 10 years, so I don't think the whole house AC opton really pans out

Any one have any links to sites that purport to give fomulas fo determining what sze BTUs) unit for what siz spaces?

House is a tri-level. Main level has 24' x 12' living room; 12' x '12 dining room, 14' x 12 kitchen, and a sort of 8' x 6' foyer that leads to staircases up and down.

Upper level has hall that runs almost width of house; master bedroom and bath, about 20' X 14'; at one end of hall; largish bedroom at other end of hall about 14' x 12; smallish bedroom next to that about 10' x 12'; full bath about 6 ' x 8' .

Lots of doors, etc off that hall to rooms.

Lowest level has short hall at bottom of stairs running along the width of the house from left to right; 12' x 22 family room with big french door set with side lites that open, no other windows; full bath and laundry room opening off middle of hall and another large ish 14' x 14' (?) bedroom off other end of hall.

I'm thinking unit in upstairs master bedroom; unit in LR and unit in downstairs large bedroom?

Opinions, thoughts, guidance, heat jokes all welcome.

Thanks.

[Pat]

Okay, since you're open to heat jokes, etc., how about useless suggesstions like what we call "swamp coolers"

I don't khow about sizing. I go read the box at Walmart.

[Joseph Meehan]

Frankly now would not be the best time for you to get one. Those selling them are going to have their prices up and selection down in your area.

Start by asking yourself if you are going to try and cool the whole home or just a few rooms.

If you are going to cool just rooms, consider buying just one unit at first and size it on the small size for the largest area. Then you can move it to a different area if it is too small. You DON'T want to get something too large as it will not de-humidify properly. From that first test you can then make better guesses about the other smaller rooms or maybe a larger one for the large room.

Don't buy for today's weather, but for a little less warm weather.

Personally I would suggest considering hiring a HVAC professional to look at your home, do the numbers and add his experience of your areas construction and weather to make some suggestions.

[Bill]

This time of year you take what you can get and that is if you can find a window A/C anywhere. New units use half the electricity of old units, so only buy a new one. I have a 10,000 BTU window A/C in the bedroom and it keeps several rooms cool or on very hot days like we have been having, it keeps the bedroom cool and adjoining rooms somewhat cool.

The best time to buy a window A/C is in late winter. I purchased mine one year when it was snowing and there were 3 other people doing the same thing! (We were too hot the summer before and all stores were sold out...) The stores around here have winter stuff in the late summer and summer stuff in the late winter.

[Joseph Meehan]

Pat wrote: ..

The OP is in Washington State. Unless they are on the east side of the mountains, I doubt if a swamp cooler is going to help. :-)

[Jim McLaughlin]

I appreciated the swamp cooler joke and the shop cooler joke.

Regarding reading the boxes at Wallyworld, the nearest one i a 30 mile drive 'cause we here in Portland are so politically correct pure and our city council don't let no low price competitors do business here.

And I'd rather no rely solely upon the boxes, or a salesman at the local appliance emporium.

Off to the library to look at Cnsumer Reports.

-- Jim McLaughlin

Reply address is deliberately munged. If you really need to reply directly, try: jimdotmclaughlinatcomcastdotcom

[Jim McLaughlin]

Good points.

[udarrell]

All of the formulas I have seen are way off, they oversize by a mile! A lack of air circulation is the smaller unit's major shortcoming, so you need to supplement the airflow!

I cool the first floor over 900-S.F. of a 1934 with a mere 6,000-btuh half ton ultra quite Whirlpool window unit. Yes, we have the rare 100+ days too and it handles it just right. It said on the box that it cools rooms up to 225-S.F., it cools over three times that area and does it perfectly!

You have to use a floor fan and read my page on how it is done. - udarrell

[Edwin Pawlowski]

You can try this one

This is not perfect in that there are any factors to consider. Exposure, contruction types, widnow area, and on and on. But they are pretty close for most uses.

Yes, it can work. What is the real goal? I fit is to be comfortable sleeping, get bedroom sized units there and at night or unoccupied times, close the doors and let the rest of the house be hot. If you want all over cool, all the time, figure the total cooling needed, then come up with a distribution plan.

Tri levels can be difficult. You can't easily cool an upper level with one unit doing more than one room, unless the lower level is also cooled. The cold air will be going down and the small AC will struggle. With the downstairs cooled already, not a problem.

In my case, a bi-level, I have three units. Lower level (most occupied) is cooled all the time. Second level, has a bedroom unit on all the time in the heat. The rest of the house is not cooled at all some days. When it is, the dining room unit is turned on, but a fan is needed to move the cold air out to the rest of that level. Only then is the bedroom door left open for full circulation. Two unused rooms are closed off during the cooling season.

Room units are not as efficient as a central unit, but it can be very economical if done properly. If I lived in Arizona, I'd have central, but here in New England I can't justify adding it now.

[Jim McLaughlin]

In the upstairs master, need to be able to sleep. A small room sized unit should do it.

On the downstairs level, in the big downstairs bedroom, my 91 year old mother lives here now. She spends a lot of time in the family room on that level which has the 37" TV that she can actually see with her macular degeneration. That family room has a big set of doors, with additional side lites, but no actual window in which to install a unit. I think tahts a big unit in her BR with a fan or two to circulate down the hall to the FR.

The main level with the living oom, dining room and kitchen is used and daily cooling would be nice. I think tahts the big unit, too, in the LR.

I found a site on

that purports to calculate sizes for room ACs.

I'll compare the CS results with the results from the site you reported.

Thanks for helping me clarify and focus my thinking on this.

-- Jim McLaughlin

Reply address is deliberately munged. If you really need to reply directly, try: jimdotmclaughlinatcomcastdotcom

And you know it is a dotnet not a dotcom address.

[Gideon]

Joseph,

Good suggestions, but I have one concern. As busy as they are, plus considering the fact that the OP doesn't want to purchase a permanent system, how many HVAC techs are going to want to come out and evaluate the OP's requirements?

Plus, if he is going to spend a few hundreds dollars on window AC units, does it really make sense to spend a few hundred additional dollars to have a pro "do the numbers"? He should spend his money on actually hardware, in my opinion. Especially since he has indicated that he really doesn't need AC very often. All he needs is a few window units to get him past a few horrible days each summer.

Gideon

================

Joseph Meehan wrote

Frankly now would not be the best time for you to get one. Those selling them are going to have their prices up and selection down in your area.

Start by asking yourself if you are going to try and cool the whole home or just a few rooms.

If you are going to cool just rooms, consider buying just one unit at first and size it on the small size for the largest area. Then you can move it to a different area if it is too small. You DON'T want to get something too large as it will not de-humidify properly. From that first test you can then make better guesses about the other smaller rooms or maybe a larger one for the large room.

Don't buy for today's weather, but for a little less warm weather.

Personally I would suggest considering hiring a HVAC professional to look at your home, do the numbers and add his experience of your areas construction and weather to make some suggestions.

[Gideon]

Jim,

Remembering your questions, I made a side trip yesterday at Sam's Club to check out their window AC units. Some suggestions and observations that resulted from what I saw:

1) 5000-6000 BTU window units were about $90 and had SEER ratings of 9.7 to 9.8. 2) 10,000 BTU window units were about $170-$190 and had similar SEER ratings. 3) I would expect prices at WalMart to be about 10% higher? 4) There was a decent supply and selection still available. 5) All units were the sort in which you must install some permanent bracketing to support the unit. You should consider if this is the type that you would prefer. Many small units have accordian side pieces and are designed to pop in and out of a window very easily and quickly. I prefer the highly portable units for folks such as you. At the end of the cooling season, the units can be removed quickly and there is no evidence that they were ever in the window. 6) All units that I saw were 120v. Avoid 240v units unless you want to do some house wiring. 7) As I indicated in another post, I would suggest crunching your own numbers and not hiring a pro to evaluate your requirements. At Sam's Club prices, you can purchase 2 small units and a larger 10,000 unit for $360. For your modest AC requirements, you may determine that those 3 units would be very adequate. No matter what you compute, you probably won't be off by much if you make a reasonable effort to compute carefully. And the money you save by not bring in an HVAC pro will cover a large part of the cost of your AC purchase. 8) Both Sam's Club and WalMart have online sites where you can search for AC units, check prices and place an order. Obviously, you must be a Sam's Club member (or have a friend who is a member) to order from their site. 9) You can wait until December to save a few bucks on your AC. You can also do all of your restaurant dining at 4PM or 11PM to save a few bucks on meals. Personally, I make a purchase when I need it. If you wait until winter to buy the AC units, how much will you actually save and will it be worth going through the rest of this summer without AC? 10) Sam's Club (and WalMart) have powerful floor fans for about $30. Those help move the air around the house quite well. Do you have central forced air heating? If so, running the furnace fan continuously when the AC units are in operation helps move the cool air throughout the entire house, if that is your goal.

Good luck, Gideon

===============

So I'm thinking about the room AC option. I'm not intending to stay in this house more than another 8 - 10 years, so I don't think the whole house AC opton really pans out

Any one have any links to sites that purport to give fomulas fo determining what sze BTUs) unit for what siz spaces?

House is a tri-level. Main level has 24' x 12' living room; 12' x '12 dining room, 14' x 12 kitchen, and a sort of 8' x 6' foyer that leads to staircases up and down.

Upper level has hall that runs almost width of house; master bedroom and bath, about 20' X 14'; at one end of hall; largish bedroom at other end of hall about 14' x 12; smallish bedroom next to that about 10' x 12'; full bath about 6 ' x 8' .

Lots of doors, etc off that hall to rooms.

Lowest level has short hall at bottom of stairs running along the width of the house from left to right; 12' x 22 family room with big french door set with side lites that open, no other windows; full bath and laundry room opening off middle of hall and another large ish 14' x 14' (?) bedroom off other end of hall.

I'm thinking unit in upstairs master bedroom; unit in LR and unit in downstairs large bedroom?

Opinions, thoughts, guidance, heat jokes all welcome.

Thanks.

-- Jim McLaughlin

[udarrell]

All of the formulas I have seen are way off, they oversize by a mile! A lack of air circulation is the smaller unit's major shortcoming, so you need to supplement the airflow!

I cool the first floor over 900-S.F. of a 1934 with a mere 6,000-btuh

9.7-EER half ton ultra quite very good airflow remote control Whirlpool window unit.

Yes, we have the rare 100+ days too and it handles it just right.

It said on the box that it cools rooms up to 225-S.F., "it cools Four (4) times that area and does it perfectly."

"The new linked chart at .90 for my area, calls for 19,600-btuh daytime

3.26 times more cooling btuh than needed using a properly placed floor fan, and 14,740-btuh used for nighttime cooling (ridiculous)."

You have to use a floor fan and read my page on how it is done. - udarrell

[Joseph Meehan]

I was expecting the OP to pay for the techs time. I suppose a tech may be willing to come out and do the numbers to provide a bid to supply the system, but they were not be obliged to give that information to the OP with it being paid for.

I am a firm believer that having properly sized equipment is key to having equipment that will provide the best comfort and lowest overall cost. To me it would be well worth the cost. I did try to suggest a procedure that might help increase the odds that the OP would end up with properly sized equipment without the professional advice.

While some have suggested web sites and these are good sources of information, you always need to remember that they are average numbers and each area has different needs for heat loads and humidity control. That is why I often suggest a LOCAL professional as the best solution. Local conditions should be considered and not just typical high temperatures.

[Edwin Pawlowski]

I agree. For many of is in rather mild summer climates, that lowest overall cost is merely a $88 unit in the bedroom window for 10 nights a year.

Many of our homes were built with hot water heat (no ducts), were built before AC was invented and a retrofit is very expensive. Anything can be done, given enough time and money, but sometimes the cheap way out is really the best.