excessive heat, how do you protect your house during a heat wave?

[electrolyte]

Main HVAC unit in my house finally pushed me too far last year and I had it replaced. It was a 'nice' unit at the time it was bought, scroll compressor, high seer rating.

As part of the replacement, my HVAC guy went through and did airflow measuring/rebalancing at each air vent along with the return line itself.

Turns out, the return line was only sized for about 60% of what it should be. This creates negative pressure on the return, which pulls air into the unit from wherever it can... and this is almost always UNconditioned air.

Both old/new units were 4 ton. The old ran nonstop on days above 95.

The new one still cycles off/on like normal on 95 days, and the compressor never gets out of the first speed.

So, boys and girls, airflow matters. Duct sizing matters. Air leaks, especially HOT attic air, really matter. House has never been this comfortable either. Indoor humidity is lower also.

In the olden days, every room had a supply and return. That is best, but costs a lot. Yes, badly sized ducts and duct leaks cause pressurization or depressurization and turn your air handler into a power vent forcing out conditioned air, and maybe worse, sucking in humid outdoor air where water condenses at the first cool surface it hits. Even with good, well-designed ducts if you have central return(s) closing and opening doors can cause pressure differentials if proper room to room flow is not designed in. A home should be every so slightly pressurized.

 

[electrolyte]

Cool metal roofs do help, most of the time a lot depending on what kind of construction. But they should be a good deal with almost any kind of home roof system. You do need some slope. Years ago, the Florida Solar energy center produced a lot of very good data comparing roofing. They have real numbers and little hand-waving. The roof does not have to be white, but white was the most reflective so best from a heat gain standpoint. One of my neighbors has a standing-seam metal roof with sort of salmon-colored ridge caps as a stylistic nod to tiled roofs. I like it.

 

[turbodog]

...cool the attic passively. ...

Yeah, but when the attic passed 145F it was time to do something. Simply not enough room at the ridges for venting this many sq ft. Hip roof so no gable vents were possible.

You literally could not go up there in the summer. Even plumbers and HVAC people said 'no'.

The fan only moves a few hundred CFM. The eave vents can easily meet this airflow.

Temp dropped ~25F give or take.

And w/ a concrete slab foundation... HVAC is all in the attic.

 

[KITROBASKIN]

Taking a page from MrCool (pulling a vacuum not necessary) and getting a high efficiency rating for such a small unit, the owner of diysolarforum, Will Prowse, put out a YouTube video recently on this unit:

EG4 9K Mini-Split Air Conditioner Heat Pump | 9000 BTU | SEER2 29.5 | Plug-N-Cool Do-It-Yourself Installation

Signature Solar provides solar panels, off-grid solar systems, grid-tie, and hybrid systems. Quality solar inverters, bifacial solar panels, complete solar kits, solar batteries. Featuring brands such as EG4 Electronics with their solar battery, LifePower4 and EG4 LLifePower4 and EG4 LL

signaturesolar.com

This would handle our very small straw bale structure (with the measures already being employed like window insulation) and our modest solar capability would probably power it for the most part. Extended cloudy days yet still hot would not work.

 

[Poppy]

We have gas heat and hot water. The boiler, and hot water heater each have a pilot light. I don't know how many BTUs each puts out, but during the summer months, I won't need the furnace to come on, so I turned the gas off to the furnace.

Each BTU saved from being produced inside the house, the fewer the AC needs to cool.

 

[Poppy]

It's 5:00 AM... 72F with 90% humidity. We'll keep the windows closed, and the AC on filtering the air, and cooling/dehumidifying as needed.

 

[orbital]

+

Finally set up my self-inflating mattress (bed) yesterday in my basement where it's much cooler.
Wasn't sure how it was going to go last night,, but gotta say, it was surprisingly comfortable.
... it's like 90% memory foam, then the 10% air in it keeps its shape.
Added a bit too much extra air and it was too firm ,, let a bit out in the middle of the night. All good!
Found my Honeywell air purifier fan & had a comfortable sleeping setup.
Didn't loose any air & gotta say rather impressed.

The longer length makes a big difference I would gather

got a very good deal while back, it's this mattress

Amazon.com

 

[Galane]

For a small, about 750 square feet, house I'm looking for a quiet fan that can be put in a duct to pull air from the living room ceiling and blow it into the two bedrooms and bathroom via ducts and ceiling vents. There's a freestanding gas heating stove in the living room next to the short hallway to the bath and bedroom doors.
There's a 18K BTU mini split inside unit on the dining room wall, set up to blow across the dining room into the living room.

The kitchen is open to the dining room and through the kitchen is an open doorway to the utility room. So everything other than the living room and dining room only get heated or cooled by whatever comes in via convection. Since the house is so small it does work but the bedrooms, bath, and utility room are always colder or hotter. Especially colder when just the gas stove is used in winter.

Ducting from the living room ceiling to the kitchen and utility rooms would also be nice to do. Not having a loud fan or two roaring is the tricky part. There just needs to be some amount of forced flow to 'smooth out' the temperatures.

 

[IMA SOL MAN]

For a small, about 750 square feet, house I'm looking for a quiet fan that can be put in a duct to pull air from the living room ceiling and blow it into the two bedrooms and bathroom via ducts and ceiling vents. There's a freestanding gas heating stove in the living room next to the short hallway to the bath and bedroom doors.
There's a 18K BTU mini split inside unit on the dining room wall, set up to blow across the dining room into the living room.

The kitchen is open to the dining room and through the kitchen is an open doorway to the utility room. So everything other than the living room and dining room only get heated or cooled by whatever comes in via convection. Since the house is so small it does work but the bedrooms, bath, and utility room are always colder or hotter. Especially colder when just the gas stove is used in winter.

Ducting from the living room ceiling to the kitchen and utility rooms would also be nice to do. Not having a loud fan or two roaring is the tricky part. There just needs to be some amount of forced flow to 'smooth out' the temperatures.

You need on-site inspection by a professional HVAC person, IMO.

 

[raggie33]

i pay homeless people to spit on me. but this has nothing to do with the question lol. i have 4 acs runing its so damn hot and humid here what a crazy summer

 

[Galane]

You need on-site inspection by a professional HVAC person, IMO.

In this State people are allowed to do their own HVAC work.

 

[IMA SOL MAN]

In this State people are allowed to do their own HVAC work.

That's fine, but a pro could help you with your questions.

 

[IMA SOL MAN]

For cooking, induction hobs are generally a lot more efficient at getting the food hot rather then the room. That said, they are a little overrated compared to a big pot on a resistance coil at moderate heat setting. That is pretty efficient. But if you are bringing up a pot to boil quickly, induction is king.

Not exactly related to the induction stoves because this is a different type, but I just got an email newsletter announcing this release from the CPSC, so I thought it timely to post, because it is news to me, and it might save a reader some pain.

Whirlpool Agrees to Pay $11.5 Million Civil Penalty for Failure to Immediately Report Glass Cooktops Posing Burn and Fire Hazards

Whirlpool Agrees to Pay $11.5 Million Civil Penalty for Failure to Immediately Report Glass Cooktops Posing Burn and Fire Hazards

www.cpsc.gov

 

[electrolyte]

For a small, about 750 square feet, house I'm looking for a quiet fan that can be put in a duct to pull air from the living room ceiling and blow it into the two bedrooms and bathroom via ducts and ceiling vents. There's a freestanding gas heating stove in the living room next to the short hallway to the bath and bedroom doors.
There's a 18K BTU mini split inside unit on the dining room wall, set up to blow across the dining room into the living room.

The kitchen is open to the dining room and through the kitchen is an open doorway to the utility room. So everything other than the living room and dining room only get heated or cooled by whatever comes in via convection. Since the house is so small it does work but the bedrooms, bath, and utility room are always colder or hotter. Especially colder when just the gas stove is used in winter.

Ducting from the living room ceiling to the kitchen and utility rooms would also be nice to do. Not having a loud fan or two roaring is the tricky part. There just needs to be some amount of forced flow to 'smooth out' the temperatures.

Will in-wall jump ducts help? They are often used in super-insulated homes with one few mini splits. You can use blowers for them although they are often used as passive returns to facilitate return air from rooms with no return. They can be installed in two ways. You can open a stud space and seal it. Sealing is very important. Then, replace the drywall. Install a grate near the floor on one side and near the ceiling on the other. One grate will have a blower. The method I prefer is to have duct between the grates rather than sealing the stud space. See what Tamarack and Tjernlund have to offer. I'd avoid jump ducts running through the attic. It is always better to keep stuff in the envelope.

 

[turbodog]

Leaving the HVAC in circulate mode is an option. Any fan running will introduce heat into the structure... something to keep in mind regardless.

 

[Stress_Test]

So, in the winter time, can I heat my bedroom by running several fans?

 

[raggie33]

So, in the winter time, can I heat my bedroom by running several fans?

no

 

[Stress_Test]

no

To paraphrase from Forrest Gump: "Holy s*** Raggie, you are the smartest man on this entire gol'darn flashlight forum!!!"

 

[idleprocess]

So, in the winter time, can I heat my bedroom by running several fans?

In theory, yes, because the fan motor is going to radiate some waste heat.

 

[IMA SOL MAN]

So, in the winter time, can I heat my bedroom by running several fans?

It will depend on the amount of heat they give off, verses the heat loss of your house. Then there is the wind chill effect of the moving air on people and animals...