Window AC with central air ?

Been hot as blazes this week and central air unit struggles to keep up. Runs all day just to keep house cool. I turn up the thermostat at night to give it a break. I thought about adding a window AC unit to the living room to help keep the main area cool since no one is in the bed rooms etc, much. Single level ranch style home. Is it more efficient to run this set up or just set the central air at 73* and leave it there day and night ? -Thanks

Sounds like you need your central air serviced.

That or a new one sized properly.

As you do not say the age of the ranch house, the insulation, the age of the central air or if you have had it serviced, there is a reality in this in my part of hotter than Hades.

For some reason people think that they can run big screen televisions, cook like it is Thanksgiving and find other flame throwers to heat a house up, and then are puzzled why on hot summer days their central air won't keep their house at 73 Siberia conditions.
There are things that help like closing the shades on the windows, running small fans to move air, and the novel idea of closing the doors on rooms not used, including closing the central air to them, so it is concentrated in living areas.

In most cases in our home, we have evergreens planted on the north side of our house. We leave the windows open, with a fan running, except in 90 plus degree weather, and that maintains the house in the mid 70's. At night the windows are open and the house cools off, and is shut up by 9 AM if it is a hot day, so the cool air stays inside.

We cook on cool days, and eat pasta, salads or grill and except in the hottest periods of 75 degree nights, the house is cool and we rarely run the AC.

The heat and humidity the upper Midwest has been having this past month is now moving east and our area is being given a break. In almost every case a window AC should cool a house, as should central air. If you are having the problems you are with not heating the house up, your central needs to be serviced as others have rightly said, but if you are heating the house up from the inside, then it is not the outside temperatures.

X3
Set it at 73 and see how it works out for a week. Window ac can be expensive upfront if you don't have one. If you do install one, make sure it's very secure and level.

Have u changed your filter lately? My house wouldnt cool below 75 last week. Changed the filter and temp dropped. The filter wasnt horribly old, maybe 4 months, but it was dirty and thats what did it.

Kyron4 can you give the the outdoor temperature,indoor temperature and the cold air supply temperature. As mentioned change the air filter. Has the condensing unit outdoors been cleaned? If not take a garden hose and you don’t need to shut the unit off- spray the condenser coils with the garden hose start on one side from top to bottom. If you use too much water pressure you can bend the coils fins. Too little water pressure and you won’t push the dust,pollen and grass clippings out of the coils. You can also after cleaning the coils if it’s 90 degrees outside let a sprinkler spray a little water on the condenser coils if you have your own well. I don’t like spraying water on them for more than a week or lime scale can buildup on the coils. Feel free to pm me

As I understand it, a properly sized furnace should run almost nonstop in an extreme cold snap, and the AC should do the same in a hot spell. As noted money spent on insulation and tightening up air leaks is money very well spent. Can't speak to the window unit idea, but it seems to me it might help relieve the central unit, but might be cost prohibitive. Ceiling fans and small box fans to move the air around is a proven help. Let us know what you do and if it helps.

Several good points have already been made...also, keep in mind that most home A/C's are sized to drop about 20 degrees'ish. So if it is 95+ outside...you may only be able to get down to 75'ish. As others have said...check your filters, close off unused rooms, draw your blinds, etc.

I change filters every 60 days, our unit is 23 years old.

mine went out last year at 25 years so you better start saving up your pennies....

It would probably help but depending on your electric rate you may go broke running it.

Pm sent

Okay let me give more details. All windows have blinds and room darking drapes closed (no sun light gets in), ceiling fans in all living spaces, box fan in hall way, all unused rooms have doors closed (closing air vents is not recommended as it strains the system per my HVAC man), we don't used the oven or stove, we eat "light" meals in the summer or cook out. So ya, I have taken all the steps to keep the heat down inside.

System is about 20 years old, clean filter every month, cond. coils kept clean, unit in the shade, etc. It was 96* today with a 110* heat index, low was 79*. House stayed cool at 73*, but unit ran non stop from 9 am to 9 pm. I realized it is approaching the end of it's lifespan, but it is still working and was inspected a year and a half ago. Thermometer on vent reads 57* to 59* so it still produces cold air, though blower seems weak. I see a new one in the near future , but for now I have to get by as is. I just thought a window unit might give it a break on those really hot days.

including an attic fan to pull all THAT heat out, so it doesn't heat your rooms' ceilings?

We had a similar problem with our upstairs central air unit, it struggled to keep our house at 76, not exactly overly cool IMO. So we invested in a backing material for our curtains on the west side of our house to keep the sunlight out along with a solar roof fan that pulls the hot air out of attic once the air reaches a specific temperature. These 2 things have helped a great deal.
Our CA unit was 22 yrs old and we replaced it about 6 weeks ago. We went up a half ton in size and a few hundred higher sear?? Only problem was the house was plumbed for a 2 ton unit and I think it has 5/8” copper and the new unit called for 3/4”, according to the mfg we’d loose about 3% efficiency due to the smaller line. In talking to our AC guy, we figured a 2019 unit would still be far more efficient than 1998 unit, despite giving up the 3%. It’s been miserable lately, heat n awful humidity with the heat index running well over 100. This new unit runs much less in duration and less often, all the while we’ve lowered the target temp in our house by a couple degrees. I’m anxious to see our electric statement this month to see how this new unit has impacted bill. Fingers crossed LOL!!!

Air conditioning? Townies!!

Kyron4 sounds good. If you could mist some water into the condenser coils it would let your air conditioning work a lot easier . You could put a stake in the ground and attach the garden hose spray handle and have just mist some water into the coils. It would make a huge difference in the a/c capacity.

Closing vents and doors to unused bedrooms is exactly what I do. I can think of no reason that closing a few vents would "strain" the system. It would put a bit more load on the fan perhaps but not on the high dollar components of the unit (the compressor and coils). To me a unit that is struggling and running continuously on the very hottest days of the year is probably sized just right. So what if it is a few degrees warmer in the house for a few days of the year.

I would not invest in a window unit especially since your main unit will need to be replaced in a few years. A slight upgrade in the main unit would be money better spent.

Has the blower fan been removed and cleaned in the past several years ? Proper air flow along with the the other things noted are all required for proper cooling. That temp at the vents can be misleading. Take the temp at the filter and the temp at the closest vent and see what the difference is. It should be in the 16 to 20 degree range. A dirty blower wheel happens so gradually that it is often overlooked but can cause major issues as far as cooling in high outdoor temps. Also check the duct work to make sure you don't have leaks causing a loss of pressure at the vents. Again air flow being a major factor in the equation. don't assume that because you keep up with your filters and keep the coils clean that the fan blades haven't become dirty. I find this issue constantly and always check/clean the blower when servicing a unit. All the other suggestions are spot on. The first question I generally ask in these situations is " How was it doing in similar conditions prior to this?" That answer can generally point you in the correct direction.