Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.

--
"I miss. I miss. I miss. I make."
Seve Ballesteros describing his four-putt at Augusta's No. 16 in 1988.

The obvious question is: How cold is the air coming out of the vents?
Also, is your attic properly vented (or have an exhaulst fan)?

badgolferman wrote:

Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.

--

Yes to both. BTW fans do not cool your house they cool the people in the
house.
You might get free advice from the electric company. They come to the house
in NJ.

Lou

The heat load on the AC is the sum of the conduction loss through
walls, windows, etc.
and that incurred in cooling (and dehumidifying- no small challenge in
SE VA) infiltration from leakage.

Can we assume the system was running non-stop?

Not knowing what energy-conservation measures are in place, it's a SWAG
as to what measures would benefit you most. SWAG taken.

Suggestions:
1) Replace filter- too cheap to quibble unless it's new. See that all
air-movers are moving air. Probs- see 5.
2) See that all windows, including storms are closed. Tightly.
3) Look for the obvious air-leaks, like all door-seals, especially at
top and bottom of enclosed volume of house. Chimney-effect thing.
4) Close shades, especially facing S & SW. No shades? Good
investment.
5) If A/C has not been checked/serviced within a year, schedule it now.
Better techs will be busy, and you don't want a hack/salesman. Ask
what checks or basic servicing you should do regularly.

Vaulted ceilings will make it difficult to retrofit proper ventilation,
but you might check that you've sufficient soffit vents if there's a
ridge vent. Which I'm assuming. (There really should be a "channel"
for air-flow from soffit vents, between insulation and roof-deck, out
ridge vent. To reduce heating of house and frying of shingles.)

Ceiling fan in "great room" mainly mixes hot air above with cooler
below. Sub-optimum. You'd get better perceived cooling with small
circulators moving only air down at human-level. "Vornado" comes to
mind- works for me.

OTHO, 84 vice 102 is good. :')

HTH,
J

badgolferman wrote:
Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was
102. My AC is set to 78 and the inside of the house was 84. By the
time I went to bed at 11 PM it had come down to 81 inside the house.
This morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the
builder.

You have been given some good advice and information. I will only add a
few thoughts.

A/C should be sized based on the home's construction, including
insulation. There for if you A/C is not keeping you cool under "normal"
conditions, it may not be functioning as it should or it may be undersized.
Of course in large parts of the world right now, temperature is not normal
and it is much hotter than normal.

If you are unsure of the insulation, have it checked and consider adding
more. More is always better.

--
Joseph Meehan

Dia duit

badgolferman wrote:

Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced?

It could be both!

My house is 1650 sq ft "with 'vaulted'
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms." I also have two skylights (BAD) in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.



SE VA Norfolk summer design: 91-DB, 76-WB 48% Relative Humidity; near a
lot of water.
Don't use the ceiling fans in a vaulted room; hot air rises, don't bring
it down or mix it with the cooler lower level air!
Leave the hot air stratified a few feet above the occupant space level.

Where are the Return Air inlets and Supply Air outlets located; high or
low, ceiling or walls?
I don't like vaulted ceilings for cooling or heating!

Can you close off or cover the skylights?

Also, the A/C system may not be working properly!
Provide us with the make and model number of the condenser!

Check the air discharge temp rise off the condenser!
http://www.udarrell.com/ac-trouble-shooting-chart.html
- udarrell

--
Factors in the Correct Sizing of Residential Air Conditioning Systems -
Recommended Procedures for Proper Duct Sizing of Residential Air Conditioning Systems
http://www.udarrell.com/proper_cfm_b...syste ms.html

An A/C system should be sized for the design point in your area. If it
was sized for the max temp (100F+), the system would be oversized,
causing a humidity problem in your home during evenings and cooler days.

Normally, a system has a swing of 3 F. Meaning, if you set the
thermostat at 75 F, it could go up as high as 78 F during the peak heat
gain hours (normally 3:00 to 6:00 pm).

If your A/C is only having a problem during this unusually hot weather,
the system is probably working fine. The hotter it gets outside, the
lower the cooling capacity/efficiency goes for the system. High SEER
systems especially see a sharp drop in efficiency (compared to a 10 SEER).

What you need to do is reduce the heat gain going into your home. Most
designers assume that you have shades on your windows that you can close
during hot days. In well insulated homes, light through
windows/skylites can account for 40% to 50% of the heat gain in the
home. Blocking out that light, especially east and west facing windows
will help a lot.

Also during really hot weather, utilities will reduce voltage about 5%.
This will result in a further capacity drop in your A/C system.



badgolferman wrote:
Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.

badgolferman wrote:

Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.



Must be tat global warming I keep hearing about.

Too many cattle belching up methane.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."

"badgolferman" wrote in message
...
Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.

--
"I miss. I miss. I miss. I make."
Seve Ballesteros describing his four-putt at Augusta's No. 16 in 1988.

Assuming the A/C is working properly and that you were just temporarily
overwelmed, you could on those really hot days, close off a few rooms by
closing the doors and vents (just not the room with the thermostat) and cool
less of the house if that is paractcal.

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thu, 28 Jul 2005 11:55:44 -0400, Slumlord
wrote:

Also during really hot weather, utilities will reduce voltage about
5%.


I think that is an urban legend. Distribution voltage can drop a lot
more than that at each pole pig, due to load alone. Sometimes the
pigs can be taxed to more than twice their rated KVA, during on-peak
hours. They are built to take a lot of punishment.


-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQA/AwUBQunyXgIk7T39FC4ZEQKa9wCeKzmqhpzYCZ7UeFd/vUL06HzLQCcAn1C6
BQQghAkKQivZQYnToqsh7GIa
=a7PN
-----END PGP SIGNATURE-----

--
-john
wide-open at throttle dot info

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 28 Jul 2005 06:38:35 -0700, wrote:

The heat load on the AC is the sum of the conduction loss through
walls, windows, etc.
and that incurred in cooling (and dehumidifying- no small challenge
in SE VA) infiltration from leakage.

You mean the passive heat load. The total heat load is quite a bit
more than that. You forget about active load, unless there are no
humans, pets, lighting fixtures or heat generating appliances
living or in use inside the building.



-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQA/AwUBQuns+gIk7T39FC4ZEQJBcwCgxQ3iEINZCpJc/zc7uGFAhq9/cb0Anj6o
X2hHMV7yPXouq7NowWgy1X6Z
=+ZFK
-----END PGP SIGNATURE-----

--
-john
wide-open at throttle dot info

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thu, 28 Jul 2005 11:55:44 -0400, Slumlord
wrote:

An A/C system should be sized for the design point in your area. If
it was sized for the max temp (100F+), the system would be
oversized,
causing a humidity problem in your home during evenings and cooler
days.

A-ha! That's why it is common to see window boxes installed in homes
along with properly sized central air, in places like Los Angeles.
An extra 8000 BTU/hr can really help out in a kitchen during a heat
wave. A 5000 BTU/hr unit can help in the bedroom of a house full of
children, when the parents want to keep the door sealed for privacy.
And there are other situations...

But I disagree about oversizing, to a point. 20 or 25% oversize
isn't going to hurt that much, with a well designed package and a
variable or multi speed blower. The better systems can be made to
unload quite nicely on milder days, without excessive short cycling.
There will be a very slight loss of efficiency, if any. But a
too-small system can't perform any magic.

-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQA/AwUBQunwlwIk7T39FC4ZEQJEqQCgnKdbt3nlvnDDuKGZ7bpWwo 3EXYcAoJV1
LrkOm8U7F0HZ3HlrTqAaEShT
=st/J
-----END PGP SIGNATURE-----

--
-john
wide-open at throttle dot info

"Joseph Meehan" wrote in message
. ..
badgolferman wrote:
Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was
102. My AC is set to 78 and the inside of the house was 84. By the
time I went to bed at 11 PM it had come down to 81 inside the house.
This morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the
builder.

You have been given some good advice and information. I will only add
a few thoughts.

A/C should be sized based on the home's construction, including
insulation. There for if you A/C is not keeping you cool under "normal"
conditions, it may not be functioning as it should or it may be
undersized. Of course in large parts of the world right now, temperature
is not normal and it is much hotter than normal.

If you are unsure of the insulation, have it checked and consider
adding more. More is always better.

--
Joseph Meehan

Dia duit


#1 complaint in VA and NC, SC the past week has been this one.

Normally, no one took the time to explain something called design temp to
the homeowner, and prob 50% of the calls were based upon that.

"badgolferman" wrote in message
...
Yesterday in SE VA the heat was so oppressive my home AC was
overwhelmed. At 4 PM when I came home the temperature outside was 102.
My AC is set to 78 and the inside of the house was 84. By the time I
went to bed at 11 PM it had come down to 81 inside the house. This
morning it is at 78 again.

Is this a function of the poor insulation of my house or is it likely
my system needs to be serviced? My house is 1650 sq ft with vaulted
ceilings and one ceiling fan in the great room and ceiling fans in the
bedrooms. I also have two skylights in the great room that I hate
which contribute to heat in there too. I believe the system is 2 or
2.5 tons; the original barely adequate system installed by the builder.

--
"I miss. I miss. I miss. I make."
Seve Ballesteros describing his four-putt at Augusta's No. 16 in 1988.

This is Turtle.

Well you need to get some one to explain to you what design temperature is and
why the contractor did not put a unit sized to take care of any temperature over
95ºF and when it get 102ºF outdoors your going to get hot. Maybe it will make
you feel better while your hot in your home.

I would have your unit serviced to see if it is anything wrong there.

TURTLE

~^Johnny^~ wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Thu, 28 Jul 2005 11:55:44 -0400, Slumlord
wrote:


Also during really hot weather, utilities will reduce voltage about
5%.



I think that is an urban legend.

-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQA/AwUBQunyXgIk7T39FC4ZEQKa9wCeKzmqhpzYCZ7UeFd/vUL06HzLQCcAn1C6
BQQghAkKQivZQYnToqsh7GIa
=a7PN
-----END PGP SIGNATURE-----



Its not an urban legend. If you check out PJM's website (thats the grid
for the mid Atlantic states), part of their emergency procedures, during
periods of very high load, is to drop the voltage on the system by 5%.
Its the last step before they initiate rolling blackouts

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On Sun, 31 Jul 2005 14:59:47 -0400, Slumlord
wrote:

~^Johnny^~ wrote:

On Thu, 28 Jul 2005 11:55:44 -0400, Slumlord
wrote:

Also during really hot weather, utilities will reduce voltage
about 5%.

I think that is an urban legend.

Its not an urban legend. If you check out PJM's website (thats the
grid for the mid Atlantic states), part of their emergency
procedures, during periods of very high load, is to drop the
voltage on the system by 5%. Its the last step before they initiate
rolling blackouts

OK, I'm convinced, but that's crazy. The maximum theoretical power
savings would be 9.75%, in a purely resistive (heating) load, with
no motors or computers, etc.

Most computer switching supplies, ac motors, etc, will simply draw
more current as the mains potential drops. All cutting the voltage
wilt do is dim the lights, and they'd be lucky to save 3 or 4% at
the most in the process, with rolling blackouts (rotating outages)
imminent anyway.

During our last power shortage here on the west coast, PG&E actually
had informed the media of which Rotating Outage blocks were scheduled
for blackout. With, like, 30 or so RO blocks in most areas, the
threat of blackouts wasn't much of a deterrent, because the
customers in the rest of the blocks knew they would not lose service
during that particular scheduled outage.

If they would black out the blocks at random, with little or no
notice, it would be a much greater deterrent to excessive usage, as
everybody would cut back - not just those in the next few scheduled
RO blocks.

And I don't buy the arg "they have to give customers ample notice
before disconnect..."; it is, after all, an emergency.

my two cents


-----BEGIN PGP SIGNATURE-----
Version: PGP 7.1

iQA/AwUBQu1kswIk7T39FC4ZEQL48ACgh3enSi13u1hBETbOBEplMn vhaLEAoLSJ
Yp1JFXcBrJSjrAyjtsFXHir2
=WQQu
-----END PGP SIGNATURE-----

--
-john
wide-open at throttle dot info