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Question about home A/C and energy usage
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Just got this months electric bill. 1,126 kWh used over 32 days. 35.19 kWh/day. Last months was pretty bad too at 800 kWh.

My winter electric usage is about 15% of this amount.

For the last two years I lived in an identical apt literally 200 ft from this one, but moved in order to get into a remodeled version. This summer has been especially hot, but I have never even used HALF this amount of energy in one month at the other apartment.

Just wondering if there could be a problem with the A/C unit or if this is just the effect of having a hotter than normal summer.

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Does each apartment unit have it's own individual A/C? I have seen some jobs where ducting isn't always routed properly too. Check the A/C unit and see if it's the same type-model as your old apartment. Then consider whether your new apartment is larger, on a higher floor, has more windows, or has more walls facing more sunshine than the old apartment. Check you ducts to see if cold is blowing where it's supposed to be blowing. If there's an open register grille in the basement or someplace that doesn't require A/C, then close it.

Also, check your utility bills to see if you're getting an actual reading, or an estimate.

But, it has been a hot spring and summer.

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Also, check the usual suspects. I'm assuming this is a typical central A/C setup. Make sure the coils and fins on the outdoor unit are clear of leaves and grass. Make sure the inside of the unit is clear. On the indoor unit, check the filters at the air handler and any at the return air grilles. Replace if they look dirty.

If it's not anything simple like that, you'll have to check around for air leaks or other big heat leaks. You know, door seals, missing attic insulation, stuff like that.

Also turn off the air conditioning and look at the electric meter. It could be that something else is running and using up energy that shouldn't be.

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Does the new place get more west or southern sun??? Is the new place on the top floor and the old place on the bottom??? There are many reasons why this could happen without something being wrong with the system. I had a similar experience just by moving from the first floor of my building to the same unit on the top floor...I guess insulated attic space isn't nearly as good of an insulator as a climate controlled apartment above you???

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Get a model number off of your outdoor unit and I can tell you what the efficiency (SEER) was on it when it was new

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Wow, thanks for all the info everyone!

AC Unit is a TRANE model# BWD718A100B0 (hopefully those are zeros and not "O"s.)

Old apartment faced SWS, new apartment faces WNW.

Both places are second story units. One factor is that essentially, no one lived below me at the old unit...the first floor guy was there about one day every two weeks... think he used it as a hotel room when he was in town. I think I saw the guy twice in my whole two year stay...only indication he was home was his 911 turbo or CL55 would occassionally occupy his parking spot. Don't know if the lack of an occupied unit downstairs is that big of a factor in the summer (can see it reducing heating bill in winter...not that I even use the heater).

The big problem with both apts is that the loft (which is my office) is where I spend 12hr/day and it takes a bit of extra A/C to cool it. I've always had a fan set up to pull air up to the loft adjacent the railing, and most of the vents closed downstairs. Only problem is there's only 1 vent in the loft.

Still need to look at the electric meter. They've been taking actual readings though.

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How old is that AC unit?

May need a recharge.

Is the insulation the same between both buildings? Even the roofing
material makes a difference.

Radio Shack has an IR heat gun for around $50 bucks. Costco has a
better one for about $60 bucks. Check everything to see if there are
temp differentials.

Check inside and outside at the same spots to see if the insulation
is doing it's job.

Also check the duct damper(s). One or more can be closed. Friends
office (she's a chiroprator) just found out tha her office & exam room
has been shut off by the previous tenants (NASA). Her partner's office
was nice and cool, but both in the same complex & unit.

Some duct systems has a 'summer' and 'winter' setup, where it intakes
and exhausts high/low depending on the season (heating or cooling).

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endo wrote:
Wow, thanks for all the info everyone!

AC Unit is a TRANE model# BWD718A100B0 (hopefully those are zeros and not "O"s.)

Old apartment faced SWS, new apartment faces WNW.

Both places are second story units. One factor is that essentially, no one lived below me at the old unit...the first floor guy was there about one day every two weeks... think he used it as a hotel room when he was in town. I think I saw the guy twice in my whole two year stay...only indication he was home was his 911 turbo or CL55 would occassionally occupy his parking spot. Don't know if the lack of an occupied unit downstairs is that big of a factor in the summer (can see it reducing heating bill in winter...not that I even use the heater).

The big problem with both apts is that the loft (which is my office) is where I spend 12hr/day and it takes a bit of extra A/C to cool it. I've always had a fan set up to pull air up to the loft adjacent the railing, and most of the vents closed downstairs. Only problem is there's only 1 vent in the loft.

Still need to look at the electric meter. They've been taking actual readings though.



That is a 1.5 ton unit, I'll see what SEER it was Monday when I get back to werk....that isn't much for a second story apt.

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They made that unit 1983-1987 and it ranged in SEER from 7.3 to 9 SEER.

The minimum efficiency that can be produced today for residential use is 13SEER. A new 13SEER unit would be 30-44% more efficient than your unit when it was brand new

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Again, thanks for the info everyone, really appreciate it!

Any idea at a wild guess as to the *current* SEER of my unit if it were say 20 years old?

Would give the IR gun a shot but at this point I think I'm going to move in two months when the lease is up. Not sure where, but this place is mortgage-payment expensive and $260/month electric bills for 900 square feet just isn't going to work for me.

Don't think the place has any duct dampers, it's way too small (900 sq ft I think)....and only about 5 outlet vents.

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There is a way to get the current SEER but it involves some pricey meters and instruments.

I would be surprised to see a 5-6 SEER out of a 20 year old apt unit....the apt maintenance guys are bad about installing the wrong motors and not mounting the condenser fan blade in the proper position when replacing them

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oooo ooooo oooo do me do me do me

Janitrol MLE 42-1B and CAPF036B2C whatever all that means

yay

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Mike wrote:
There is a way to get the current SEER but it involves some pricey meters and instruments.

I would be surprised to see a 5-6 SEER out of a 20 year old apt unit....the apt maintenance guys are bad about installing the wrong motors and not mounting the condenser fan blade in the proper position when replacing them


So basically this unit is consuming 2-3 times as much energy as a new one would. I'm definitely going to factor this into the next place I live. SCE is raising everyones rates significantly, and there are heavy fines (that made up much of my pervious $260 bill) for kWh over their ridiculously low baseline usage numbers.

Just out of curiousity, if I had say a 2000 square foot house (which I don't as those are like $100,000,000 in so cal) , how much more would a very high SEER unit cost versus the base model 13 SEER? Just looking at TRANE's site and it looks like they go up to 19 SEER, but no prices are listed.

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Dude, I flip out when my bill gets to $100.00 and I keep it set on 80 during the day, 78 nights and weekends. It will be right around $100ish through summer. Then the gas bill will get high and the electric will go down. This is for a 1300 sq ft house.
I got an older HVAC unit, but the house people told me it was like 2 times bigger than it needed to be therefore it never really has to work very hard. I had it repaired last year for about $200 for a start capacitor, and have never done anything else except change the filter.
Just googled it, got a two ton unit. Goodman PGB 024075-1. It has a 10 seer rating, so I guess it was top of the line when it was installed. Cooling BTUH listed as 24000 and heating listed as 56600.
I found the info here http://www.streamline-ac.com/SS-190.pdf
It seems like a pretty solid unit.

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saturnstyl wrote:
Dude, I flip out when my bill gets to $100.00 and I keep it set on 80 during the day, 78 nights and weekends. It will be right around $100ish through summer. Then the gas bill will get high and the electric will go down. This is for a 1300 sq ft house.
I got an older HVAC unit, but the house people told me it was like 2 times bigger than it needed to be therefore it never really has to work very hard. I had it repaired last year for about $200 for a start capacitor, and have never done anything else except change the filter.
Just googled it, got a two ton unit. Goodman PGB 024075-1. It has a 10 seer rating, so I guess it was top of the line when it was installed. Cooling BTUH listed as 24000 and heating listed as 56600.
I found the info here http://www.streamline-ac.com/SS-190.pdf
It seems like a pretty solid unit.


Yeah, but you go to work during the day, and of course during the weekends can turn it down when you're out. I'm home all day long during the week and have to keep cool or I won't get diddly/squat for work done.

These dicks at SCE baseline everyone the same...so I Iook like an energy hog.

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If you haven't already, flourescents are a great way to save energy, and ceiling fans will help keep things cooler with a higher temp reading. And, believe it or not, adding the thermal window tint makes a big difference on the glass temps when it's hot out. Doesn't do a whole lot in the winter. Then there are thermal curtains for the east and west sides of the house. My own power bill on a 1950 sq ft place was 168 for last month and it's been upper 90s to the 100s all month. Worse, I've got those damned cathedral ceilings in the place. I'll never buy another one with cathedrals in it, that's about another 800 sq ft of space I'm having to heat and cool and am getting no use out of it, worse you have to blare the TV to hear it. From now on, 8 foot ceilings is high enough for me, no more than 9 foot.

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endo wrote:
Mike wrote:
There is a way to get the current SEER but it involves some pricey meters and instruments.

I would be surprised to see a 5-6 SEER out of a 20 year old apt unit....the apt maintenance guys are bad about installing the wrong motors and not mounting the condenser fan blade in the proper position when replacing them


So basically this unit is consuming 2-3 times as much energy as a new one would. I'm definitely going to factor this into the next place I live. SCE is raising everyones rates significantly, and there are heavy fines (that made up much of my pervious $260 bill) for kWh over their ridiculously low baseline usage numbers.

Just out of curiousity, if I had say a 2000 square foot house (which I don't as those are like $100,000,000 in so cal) , how much more would a very high SEER unit cost versus the base model 13 SEER? Just looking at TRANE's site and it looks like they go up to 19 SEER, but no prices are listed.


Trane has the 19 SEER and Carrier has a 21 SEER 2-ton now and will have a 21 SEER 3, 4 and 5-ton by the end of the year...at this time, the only way to get anything higher than a 15 SEER is to have a variable speed blower on the indoor blower section. The problem is that once the units get in the 4-5 ton range, it is harder to get the 19 and 21 out of them.
Please notice on all the product literature, it says UP TO on it. That means only one combination (outdoor condenser and indoor coil/blower) gets that number and it is usually a 2-3 ton that does it.
To go from a 13-14 SEER system to a 19-21 SEER system, it would cost $3500-$4500 more...this includes the 2-speed outdoor unit, evap coil and VS blower. It will be about 32% more efficient when you do it though and here in Houston 80% of our summertime bill is A/C.

I just installed a 2-ton 20.3 SEER Carrier Infinity A/C unit with a Carrier Infinity VS fan coil for $8000.00. The lady had a 1986 9SEER system, she will see a 55+% increase in efficiency.

Check out my web-site...click on the Carrier logo and see the neat stuff they are offering http://www.pmhvac.com/



Last edited by Mike on Tue Aug 15, 2006 3:23 am; edited 2 times in total
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Pro wrote:
oooo ooooo oooo do me do me do me

Janitrol MLE 42-1B and CAPF036B2C whatever all that means

yay


This unit was made from 1990-1992 and was a 9 SEER nominal 3.5 ton (42,000 BTU) unit. It only got 39,000 BTU according to my info.

Janitrol/Goodman/GMC makes the cheapest unit in the market.

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If you really want to see a power savings the only way to go is a ground loop heat pump. Heat pumps affect air temperature by moving heat, so it tries to push heat into the outside when it's hot and pull it from the outside when it's cold. A ground loop heat pump doesn't exchange heat with the air, it exchanges it with the ground via a long plastic hose that is buried. If you have a pond that stays something like 12-15 feet deep year round, they can run the hose around the bottom of the pond, too. When they bury they either lay the hose in a gridlike fashion in the yard or they deep bore a hole for it. Then they run an antifreeze mix through it. Since the ground is about 55 degrees year round once you get below 6-8 feet, this means that the heat pump is trying to draw heat from 55 degree ground in the winter instead of 20 degree or less air, and is pushing heat into 55 degree ground instead of trying to push it into 100 degree air. These systems are so efficient that they do not require an emergency heater (either an electric coil or gas heater) for when it gets too cold, and they use about a third of the energy as a regular air exchange heat pump. One of these systems costs about 2000 more than a regular heat pump to install, but can save 50 or more a month over other methods of air management a month, so 3 years is the payoff date. Eventually I hope to build my own house, and this is the system I'd like to use when I do.

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Speeder wrote:
If you really want to see a power savings the only way to go is a ground loop heat pump. Heat pumps affect air temperature by moving heat, so it tries to push heat into the outside when it's hot and pull it from the outside when it's cold. A ground loop heat pump doesn't exchange heat with the air, it exchanges it with the ground via a long plastic hose that is buried. If you have a pond that stays something like 12-15 feet deep year round, they can run the hose around the bottom of the pond, too. When they bury they either lay the hose in a gridlike fashion in the yard or they deep bore a hole for it. Then they run an antifreeze mix through it. Since the ground is about 55 degrees year round once you get below 6-8 feet, this means that the heat pump is trying to draw heat from 55 degree ground in the winter instead of 20 degree or less air, and is pushing heat into 55 degree ground instead of trying to push it into 100 degree air. These systems are so efficient that they do not require an emergency heater (either an electric coil or gas heater) for when it gets too cold, and they use about a third of the energy as a regular air exchange heat pump. One of these systems costs about 2000 more than a regular heat pump to install, but can save 50 or more a month over other methods of air management a month, so 3 years is the payoff date. Eventually I hope to build my own house, and this is the system I'd like to use when I do.



We installed some of the Geothermal systems in the 90s. We had problems with leaking loops in the ground, leaking coils and the ground temps here on the Gulf Coast were so warm that it required digging deeper holes than normal...this also required more HP to pump the glycol

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