Insulating! AC!! Shade screens!!!

10 years ago

Just finished the BIG move to AC instead of "swamp cooler" in the old adobe ... with the cost of water in that town (they get you for the water and again for the sewer use), and the huge amounts of water used by evaporative coolers (250+ gallons a day), a moderately efficient AC isn't going to break the bank with utility bills. And this one comes with a no-pilot gas furnace to replace the 20-year old behemoth in the attic.

That meant insulation: every contractor and inspector who set foot in the attic told me that the insulation was pathetic ... we had maybe 4-6 inches of matted-down rock wool in most places.

So they blew in enough fiberglass to take it to R38 where possible, or as high as the structure would allow.

Oh my, the difference it makes! We only had bit more than a week between installing the AC and filling the attic with insulation (waiting on inspectors) so we don't have a good pre-insulation baseline for AC use but with the house well-cooled at night, the AC would start running in late afternoon to keep the temp under 80 (dry air, ceiling fans, 80 is comfortable to me).

After insulation, it is coasting through the day, never reaching the daytime maximum on the thermostat. It doesn't turn on until the thermostat changes settings.

A side benefit is that the previously uninsulated utility porch is no longer an oven. So heat isn't bleeding into the house from it.

The main heat losses in adobe houses is through the ceiling, so winter ought to be cheaper and cozier.

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Other energy saving measures:

1 - Shade screens. One smallish east window was the source of huge amounts of heat because it was in the sun from dawn until mid-morning. Shade screen on it dropped the porch temp about 10 degrees.

Other east windows in LR and DR, even in the light shade of some trees,m were heat sources: shade screens for them too.

2 - Weather stripping checking and replacing is ongoing, one door and window at a time.

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Comments (2)

energy_rater_la
10 years ago
last modified: 9 years ago
solar screens??

people don't realize what a difference insulation
in the attic makes...but you are living proof of it!

I see lots of attics with trampled down insulation
2" thick on attic floor. just what happens when
people work in the attic.
while there is a diminishing return on depth of insulation
it is a worthwhile investment.

my attic had flat batts..I mean 1" thick after it was trampled
on for what ever reason. after I finished the little bit of
air sealing I did from inside the attic & put in my radiant
barrier..I put R-19 unfaced in joist bays, then came
back with R-15 unfaced in the other direction. to cover
the faces of the 2x4 ceiling joists. (yeah...2x4)
(and 2x4 rafters...actual 2x4..not 1.5x3.5 )

in the additon..I found out when I changed the
roof that they had put pieces of batts at the eaves of
the roof..so that when I picked up the metal I saw
insulation...but the rest of the roof...zero insulation.
I put again...R-15 in rafter/ceiling bays of this low pitched
roof. then came back with 1" foam foil sheathing (R-7)
1" lathes and then reflective metal roofing.
huge difference. now this room is usable, whereas
before...hot in summer...freezing in winter.
nice to have the room that was previously storage!

I've done a lot of air sealing. having the luxury of a blower
door to test & see what works & doesn't..what lasts as
an air sealant & what doesn't..
when I rented this place prior to buying my utilities
were as much as the rent in the heat of the summer
& cold of winter. with propane costs high and a tank
of propane per month in the winter...air sealing
& the cases of caulk & rolls of mastic tape made
a huge difference.

I'd use a case of caulk and test...mark the leaks I missed
and buy the next case of caulk. I used the mastic tape
inside cabinets, to seal a/c supply boxes to walls..
not really necessary as all ducts are in air tight fur
downs inside the living space...but by this time..
just habit!

putting in the central 2 ton heat pump last summer
plus all the air sealing...my utility bill
hasn't been over $50 winter or summer..
and it has been the most comfortable year I've
ever had in the house.
right now its 75 degrees & 52% Rh..I've been
cooking purple hull peas from the garden.
and outside...90 degrees & 80% RH.
love my variable speed air handler unit!!

a diy air infiltration is to look for spiderwebs.
spiders build their webs where air moves.
@ ceiling moldings you need to caulk moldings
at top to ceiling & at bottom of moldings to walls.
@ window frames, sills or aprons...caulk all joints.
@ plumbing penetrations..thumb gum..same inside
cabintes thumb gum or mastic tape. usually difficult
to use caulk guns in tight quarters.
false boxing over cabinets? caulk to ceilings, and
all moldings.

use a clear caulk that goes on white and dries clear.
make a second round to make sure that the caulk
fills the gap after it dries. use backer rods for large
gaps.
I like Dap's Alex brand crystal clear 25-35 year caulk.
caulk will expand & contract as the house moves.
other products don't have the same flexibility.

congrats on your comfort, and investment!
I love a success story!
lazy_gardens
Original Author
10 years ago
last modified: 9 years ago
Energy_rater: Shade screens are maybe what you call solar screens ... a mesh screen to cover the windows to block some of the sun coming in.

We got the first bill after AC and insulation ... because the water use dropped dramatically, and the AC isn't running 24/7 like the motor for the evaporative cooler was, we actually had a lower total utility bill compared to the previous year.

A bit more on electricity, but far less on water/sewage. and lower humidity, which is always nice.
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