Ouch, thumper. I think your area gets hotter then mine. I think we peaked at about 115 yesterday; definitely over 110.

My weber in the shade is cool to the touch vs the AC condenser which gets the morning sun (and is hot to touch). I covered it w/ some shade tenting (like you might see at the beach) - experimenting to see if shade might help. Sounds like outside ambient may not influence output air temp, but that's the original question. And not sure about whether the spraying helped drop the temp by a few degrees (btw, the temp rose back up later; perhaps after the condenser heated back up again?).

I believe that the AC is undersized - friends and relatives have a larger size AC but smaller houses in similar areas, construction and absence of shade. And I believe our insulation sucks. The house is constructed relatively well but the developer cheaped out on many things: insulation, window quality, appliances and such. The AC is not one of the brands you guys typically mention and again, I think it's 3 ton 10-12 SEER and undersized. But it's lasted relatively well, both AC and furnace.

When the outside air is cooler, it can get very cold inside. But the system is struggler w/ the higher temps (105+).

So, agree that AC is undersized, probably tired and the house is not well insulated (min to code). But can't change any of that w/o spending a lot of money I don't have.

I use 3M Filtrete filters. Not sure what is indicated for my system. I just changed the filter a month ago. There are no filters at the evaporator / furnace. I think the MERV is 13.

When I do replace the AC someday, I heard that to up the size, I need to replace all the copper plumbing between condenser to evaporator to larger diameter piping; the piping is inside the wall. This sounds very expensive. Not sure what the best course of action will be. Assuming I move when I retire, then perhaps just go with parity - don't dump money into the house that I won't recoup.

Get quotes on having a company blow fiberglass insulation in your attic to R 30 (or even better R40+), it's incredibly cheap and will save you in 2-3 months during the summer on your electric bill and then your a/c won't be undersized.

Could you more economically add a mini-split to work alongside your existing system? If it's too expensive to get new pipe through the wall.

Ours is back in business… bad start capacitor. I should have bet the wife, I would have won. Just in time, it was 87 inside downstairs.

Hope you can find a workable solution to your system!

quote:

Originally posted by jimmy123x:
Get quotes on having a company blow fiberglass insulation in your attic to R 30 (or even better R40+), it's incredibly cheap and will save you in 2-3 months during the summer on your electric bill and then your a/c won't be undersized.

What a lot of people don’t seem to grasp is that insulation works to protect the home when it’s hot outside like the folks on the west coast are experiencing, not just when it’s cold outside. I’m not up to date on the current California insulation codes but most of the country is at least R-38 in the ceiling and we were installing R-50 if we had the room.

Insulation is cheap, requires no maintenance and pays dividends from day one.

If the OP’s builder just built to ode when the house was built there is a fair chance that it isn’t up to current code.

Temp using IR thermometer is reading about 80 on the ceiling, tile floors and exterior walls. About 93 at the joint between wall and ceiling. Concrete patio outside reading 130-140.

The house itself seems like a large 80+ heat source.

The walls are 80, same as ceiling. If I add insulation to the attic, would it lower the ceiling temp? Would it make a difference given the walls are 80?

Update: I don't think being under shade helps much. But the cooling the coils with water does seem to help a bit. Not significantly enough though...

quote:

Originally posted by konata88:
Temp using IR thermometer is reading about 80 on the ceiling, tile floors and exterior walls. About 93 at the joint between wall and ceiling. Concrete patio outside reading 130-140.

The house itself seems like a large 80+ heat source.

The walls are 80, same as ceiling. If I add insulation to the attic, would it lower the ceiling temp? Would it make a difference given the walls are 80?

Yes, it would make the ceiling temperature lower. Yes it would make a huge difference. What are your walls made out of? Stick built or CBS? How many inches of insulation does your ceiling have in the attic?

quote:

Originally posted by konata88:
I use 3M Filtrete filters. Not sure what is indicated for my system. I just changed the filter a month ago. There are no filters at the evaporator / furnace. I think the MERV is 13.
When I do replace the AC someday, I heard that to up the size, I need to replace all the copper plumbing between condenser to evaporator to larger diameter piping; the piping is inside the wall.

I suggest you lose the restrictive air filter.
Also, dirty coils/dirty filter equals lower airflow, which would increase the delta across the evap.
A competent tech will likely find issues with your system.

Lines can be ran on the side of the house, inside of a line set cover.
https://www.google.com/search?...rome-mobile&ie=UTF-8

quote:

Originally posted by konata88:

Can I improve the AC temp differential and thereby cool the house lower by spraying cold water onto the refrigerant coils outside? Or would that not make a difference / be in fact bad (but how different than just natural rain)?

Sorry but I am going to buck the trend in the answers given including Skins.

It's been a long time since I took heat transfer and fluid flow. But I do believe that while spraying cold water on the coils outside will help your air conditioner operate better, it's not going to cool your house lower.

How low the temperature of your house gets is dependent on how much heat (not temperature) the air conditioner can take out of the air that the air conditioner is blowing into your house. That's a function of the refrigerant expanding. If your air conditioner is working properly, it's taking out the maximum heat it can from the air it's blowing into your house. Spraying cold water on the condenser coils only makes it easier for the refrigerant to change from gas back to liquid. But that doesn't affect what happens on the other end where the heat gets taken out of the air coming to your house.

the other part of the equation is the amount of heat that is in the air. There's just too much heat to be taken out and a lot of it remains.

quote:

Originally posted by Rey HRH:

Sorry but I am going to buck the trend in the answers given including Skins.

It's been a long time since I took heat transfer and fluid flow. But I do believe that while spraying cold water on the coils outside will help your air conditioner operate better, it's not going to cool your house lower.

How low the temperature of your house gets is dependent on how much heat (not temperature) the air conditioner can take out of the air that the air conditioner is blowing into your house. That's a function of the refrigerant expanding. If your air conditioner is working properly, it's taking out the maximum heat it can from the air it's blowing into your house. Spraying cold water on the condenser coils only makes it easier for the refrigerant to change from gas back to liquid. But that doesn't affect what happens on the other end where the heat gets taken out of the air coming to your house.

the other part of the equation is the amount of heat that is in the air. There's just too much heat to be taken out and a lot of it remains.

As the outdoor temperature rises the air conditioners efficiency/capacity goes down.
So, being able to remove the heat from the condenser easier, you are gaining an increase in capacity.

Example; 2.5-ton unit:
(With 63F Wetbulb indoor entering air, fairly dry conditions)

Outdoor temps entering condenser:
75F capacity 28,150 Btu.
85F capacity 26,880 Btu.
95F capacity 25,510 Btu.
105F capacity 24,070 Btu.
115F capacity 22,650 Btu.
125F capacity 20,910 Btu.

But as I stated in my first reply, I don't recommend using a water cooling system.

One would be better served with adding a small 5,000 Btu., $100 window unit.

quote:

Originally posted by Excam_Man:

One would be better served with adding a small 5,000 Btu., $100 window unit.

This is a great idea. My central AC went out in the hottest part of summer a few years ago, and it was 3 weeks before I could get anyone in there to replace it. I bought a window unit to keep my bedroom tolerable in the mean time. After I got the central unit replaced, I left the unit in the bedroom. I've saved a significant amount of money since then because I can set rest of the house ~10 degrees warmer, and just cool my bedroom when I need to cool off. I'll probably look into a mini split to do the same thing in the future, but that's hopefully many years down the road.

quote:

But as I stated in my first reply, I don't recommend using a water cooling system.

One would be better served with adding a small 5,000 Btu., $100 window unit.

Just to be clear I wasn't recommending it as a practice. I was just saying that it is possible to reject more heat in an emergency situation.

A cheap window unit and comfortable bedroom at night is the better answer. I did this for years untill I could afford a new HVAC system. The sad part was the A/C system (plus insulation) paid for itself in a couple years. Wish I did it earlier.

quote:

Originally posted by Skins2881:

A cheap window unit and comfortable bedroom at night is the better answer. I did this for years until I could afford a new HVAC system. The sad part was the A/C system (plus insulation) paid for itself in a couple years. Wish I did it earlier.

I work commercial / industrial HVAC and typically don't do residential at all, but having installed for friends / church members in the past - this is very common with an older system. Up front cost are a good bit, but the utility savings add up quickly.

There have been several post on water cooling of outdoor coils - in the industrial market we do use sprinklers or misters on outdoor coils and have many times - BUT its always a method of last resort. Unit deterioration is virtually guaranteed (at least it was in south Florida)

Guys - lots of good info here (for me at least), especially on the benefits and adverse implications for water cooling of coils. Very good to know.

quote:

BUT its always a method of last resort. Unit deterioration is virtually guaranteed (at least it was in south Florida)

We do it all the time when temps get above 95. We rather waste 1000's of gallons of water than risk tripping one of the circuits because that would have a cascading effect and we could lose all chillers. When you need 99.9999% uptime they rather waste water and possibly shorten coil life.