Currently 115 degrees here in my part of Oregon. That's a 5 degree F temperature differential (< 3 degrees C) between here, and the hottest point in Death Valley, which is currently 120. That's... insanity.

On an unrelated question, for those of you in more typically hot climates, any preferences on AC brands between York, Daikin, or Lennox?

Carrier.

I also like Carrier.

If you are new to shopping for whole house air conditioning, there are additional factors. Such as dehumidification and, possibly critically the ability of your existing ductwork to deliver the cooled air to the necessary area is the house. And draw the warmest air into AC system.

AC turns a traditional ducted furnace house heating system upside down. The return air ducts in a heated house tend to be near the floor (aka cold air returns). Cold air tends to travel downhill so the largest capacity cold air returns tend to be low on the main floor.

In a house with AC running you want the return air intakes to be high in the rooms, ceiling intakes or high on the walls. Hot air tends to rise so if you have a two story house you may want the largest return air draw from the highest parts of the house.

Whichever you get, be sure that it is a true heat-pump model, that can be used for heat in the winter and cool in the summer. Some models can run over 200% efficiency.

tanstaafl.

I replaced my AC unit a few years ago, and went with Lennox. I couldn't be happier with it. Just as a point of comparison, the highest temperature I saw last week (during our turn at the heat wave) was 117F. This week is a more reasonable 103F-105F.

When my installer first came out to do the heat survey, we talked about what I was looking for in the system. I originally said Carrier, but he recommended Lennox. A comparable setup from Carrier would have been a few thousand dollars more (I got a new AC, air handler, and thermostat).

I can't really compare it to my previous unit, since it was around 20 years old when i got it replaced. I can say that even though the compressor is outside next to my room, it doesn't wake me up when it turns on (I'm a really light sleeper). The air handler (also Lennox) is in the attack above the closet in my room, and that doesn't wake me up either.

The only problem I've had with it in 4 years was the Smart Hub spontaneously dying. That unit controls everything, so I was without heat for a few hours until it got replaced (which wasn't a big deal). The repair guy did say that was the first hub he ever saw just die.

Our house is new(ish) -- about 12 years old. It was built with the intent to add AC -- the 40A circuit, and breakout box are already in place. The duct work should be good. It's wrapped in insulation, at least, which I'm not going to undo. And the air return is at the top of the stairs.

I'm not currently looking at heat pumps, though I've heard good things about them. That will be on the agenda when we have to do a total system replacement. Right now, we're just looking for the cooling (which we currently really only need for maybe one month of the year, climate change not withstanding).

Double check that.

We added AC to our new house a couple of years ago. Our house is newish, only about 8-10 years old at this point. The AC installation itself was fine. But the ducts that run to the upstairs are woefully inadequate in terms of size and airflow, and the single return-air vent in the hallway doesn't suck enough air through to make it worthwhile.

As a result our upstairs is about 5-10 degrees warmer than the downstairs during the summer, it'd be even worse if I wasn't doing a bunch of mitigation: I close some of the downstairs vents to get more air upstairs, but you can't do too much of that without causing excessive static pressure, which is bad for the fan and compressor. Without any return-air vents in the upstairs rooms, we have to keep the doors to all the bedrooms open at all times except when sleeping, in order to keep the air flowing. I have to program the system to run the fan 75% of the time, to keep the air circulating even when the cooler isn't on.

At least the AC held up during the heat wave last weekend. During that, my band went to our cellist's house on Saturday to video us playing an outdoor concert; it was over 100 in Redmond. Crazy stuff, but she had AC too, so we got to take breaks in the cool. That was some work, though.

The duct work in my house was also inadequate (which isn't a good thing here). It had a ton of right angles and constricted areas. They did a custom duct to get rid of all those static pressure points in the junctions that lead to the flex ducting. Also as part of the install work I had done, they added another return (since the one just wasn't enough) out in the living room. The difference was pretty dramatic.

I'll double check the ducting. I've been through both attic and crawlspace before, and don't recall seeing any right angles...

It is all about actual air flow, not just how the ducting is mechanically configured.

In a previous house I owned some of the floor registers were at the ends of very long 5 inch air ducts. The ducting was mostly straight runs, but overall was so long that the aggregate air flow reduction meant I could lay a facial tissue on each floor grill and it would not blow away.

Upgraded that room to a 10 inch round duct, plus better return air capacity (added another large duct). End result was the air flow was multiple times more effective. The AC could now easily keep up with the south facing large windows.

Ducting matters. Return air in houses is often given short shrift if it considered at all. 100% of the air that flows out into your rooms must also flow back to the furnace/AC fan. Get the return air flow right sized and properly located, and the rest of the HVAC system can do its job properly.

Can you add external shading? Our house has a lot of glazing and used to be a nightmare in summer but we added some retractable shutters last year, huge difference.

That's not a problem we have. We partially close some vents, because they blow so much air -- even the ones furthest away from the furnace. Earlier this winter, one of my kids left a balloon sitting on a register, and we got a great lesson on the Bernoulli effect.

We get by with curtains. Retractable shutters look kind of neat, but I can't see them passing the SWMBO test, over better curtains/shades.

It's a North America thing, preferring internal fabrics over durable external metal shades that double as security shutters, as seen all over Europe.

Also a UK thing &#128078;&#127995;

If I lived in tornado alley, or along the south/east coast where I'm boarding up the windows against hurricanes on a regular basis, I'd install them no questions asked (at least, now that I know about them). But they're a little overkill for this area.

Our back yard is shaded by 6 rather large douglas fir trees, which mostly shade the back windows, too. If one of them topples over in a windstorm or earthquake, those durable external metal shades doubling as security shutters aren't going to help much more than having tinfoil taped to the window.

Yep, don't know why but people just don't like them.

I don't think boarding up windows against tornadoes really happens. At least, I've never seen it.

No, surely this would be all right. I mean, it says "Heavy Duty" right on the box!

tanstaafl.