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Home > Archive > Heating and air conditioning > April 2006 > Size of A/C Unit for Room Addition-Are we being ripped off??
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| Author |
Size of A/C Unit for Room Addition-Are we being ripped off??
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| csonsini 2006-04-21, 12:21 pm |
| We currently have a 2-1/2 ton A/C unit and a 2 ton furnace for the
central heat/air
in our 950 sq foot house. We received a bid for adding a 500 sq ft
room.
Included in that bid is $5500 for a 2nd a/c unit and furnace.
The contractors were telling us that the unit(s) we have may not be
sufficient for
the total square footage that we'll end up with after the addition, and
this unit(s) would be just for the new room. I countered by saying
that we paid $3200 for the units that we currently have - and that's
for our entire house...how is it possible that we'd have to pay $5500
for 500 sq ft??? Of course, they didn't really know what to say.
Is our current set up sufficient for less than 1400 total square
footage? I know the "rule
of thumb" is 500 sq ft for every 1/2 ton, which would make our unit(s)
more than
workable. Is it the same rule for heating?
Any advice so we don't get ripped off??
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| .p.jm@see_my_sig_for_address.com 2006-04-21, 1:21 pm |
| On 21 Apr 2006 08:12:36 -0700, "csonsini" <csonsini@gmail.com> wrote:
>We currently have a 2-1/2 ton A/C unit and a 2 ton furnace for the
Alt.home.repair, not here.
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| csonsini 2006-04-21, 2:21 pm |
| Why wouldn't I post this question here??? This has to do with HVAC
(heating/ventilation/air conditioning).
..p.jm@see_my_sig_for_address.com wrote:
> On 21 Apr 2006 08:12:36 -0700, "csonsini" <csonsini@gmail.com> wrote:
>
>
> Alt.home.repair, not here.
>
>
> --
> Click here every day to feed an animal that needs you today !!!
> http://www.theanimalrescuesite.com/
>
> Paul ( pjm @ pobox . com ) - remove spaces to email me
> 'Some days, it's just not worth chewing through the restraints.'
> 'With sufficient thrust, pigs fly just fine.'
> HVAC/R program for Palm PDA's
> Free demo now available online http://pmilligan.net/palm/
| |
| .p.jm@see_my_sig_for_address.com 2006-04-21, 2:21 pm |
| On 21 Apr 2006 09:30:39 -0700, "csonsini" <csonsini@gmail.com> wrote:
Christ, here we go again.
because this is not a home-owner help goup. alt.home.repair
is. So go post there.
[color=darkred]
>Why wouldn't I post this question here??? This has to do with HVAC
>(heating/ventilation/air conditioning).
>
>
>.p.jm@see_my_sig_for_address.com wrote:
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| csonsini 2006-04-21, 3:21 pm |
| I don't need your attitude...you don't need to be a jerk.
I didn't see anything posted when I joined. I'm just trying to get my
question answered -
I looked at other postings and it seemed appropriate.
I'll be leaving the group now...thanks for the kind words
..p.jm@see_my_sig_for_address.com wrote:
> On 21 Apr 2006 09:30:39 -0700, "csonsini" <csonsini@gmail.com> wrote:
>
> Christ, here we go again.
>
> because this is not a home-owner help goup. alt.home.repair
> is. So go post there.
>
>
>
>
>
> --
> Click here every day to feed an animal that needs you today !!!
> http://www.theanimalrescuesite.com/
>
> Paul ( pjm @ pobox . com ) - remove spaces to email me
> 'Some days, it's just not worth chewing through the restraints.'
> 'With sufficient thrust, pigs fly just fine.'
> HVAC/R program for Palm PDA's
> Free demo now available online http://pmilligan.net/palm/
| |
| .p.jm@see_my_sig_for_address.com 2006-04-21, 4:21 pm |
| On 21 Apr 2006 10:51:33 -0700, "csonsini" <csonsini@gmail.com> wrote:
>I don't need your attitude...you don't need to be a jerk.
>I didn't see anything posted when I joined. I'm just trying to get my
>question answered -
>I looked at other postings and it seemed appropriate.
>I'll be leaving the group now...thanks for the kind words
Thanks for leaving.
Take your pissy bullshit with you.
[color=darkred]
>
>
>.p.jm@see_my_sig_for_address.com wrote:
--
Click here every day to feed an animal that needs you today !!!
http://www.theanimalrescuesite.com/
Paul ( pjm @ pobox . com ) - remove spaces to email me
'Some days, it's just not worth chewing through the restraints.'
'With sufficient thrust, pigs fly just fine.'
HVAC/R program for Palm PDA's
Free demo now available online http://pmilligan.net/palm/
| |
| Proctologically Violated©® 2006-04-21, 4:21 pm |
| You could probably calculate the additional load/percent capacity based on
existing duty cycle of
your unit and the % increase in area (which is about 50%).
You could get a reference point by perhaps shutting off one part of the
house, measuring the duty cycle, then opening another part, measuring the
duty cycle again, and then extrapolate to the new area.
Or use the right tables, and just calculate the load. It sorta seems like
you will be OK as is.
--
Mr. P.V.'d
formerly Droll Troll
"csonsini" <csonsini@gmail.com> wrote in message
news:1145632356.352624.25370@z34g2000cwc.googlegroups.com...
> We currently have a 2-1/2 ton A/C unit and a 2 ton furnace for the
> central heat/air
> in our 950 sq foot house. We received a bid for adding a 500 sq ft
> room.
> Included in that bid is $5500 for a 2nd a/c unit and furnace.
> The contractors were telling us that the unit(s) we have may not be
> sufficient for
> the total square footage that we'll end up with after the addition, and
> this unit(s) would be just for the new room. I countered by saying
> that we paid $3200 for the units that we currently have - and that's
> for our entire house...how is it possible that we'd have to pay $5500
> for 500 sq ft??? Of course, they didn't really know what to say.
> Is our current set up sufficient for less than 1400 total square
> footage? I know the "rule
> of thumb" is 500 sq ft for every 1/2 ton, which would make our unit(s)
> more than
> workable. Is it the same rule for heating?
> Any advice so we don't get ripped off??
>
| |
| Noon-Air 2006-04-21, 10:21 pm |
|
"csonsini" <csonsini@gmail.com> wrote in message
news:1145632356.352624.25370@z34g2000cwc.googlegroups.com...
> We currently have a 2-1/2 ton A/C unit and a 2 ton furnace for the
> central heat/air
> in our 950 sq foot house. We received a bid for adding a 500 sq ft
> room.
> Included in that bid is $5500 for a 2nd a/c unit and furnace.
> The contractors were telling us that the unit(s) we have may not be
> sufficient for
> the total square footage that we'll end up with after the addition, and
> this unit(s) would be just for the new room. I countered by saying
> that we paid $3200 for the units that we currently have - and that's
> for our entire house...how is it possible that we'd have to pay $5500
> for 500 sq ft??? Of course, they didn't really know what to say.
> Is our current set up sufficient for less than 1400 total square
> footage? I know the "rule
> of thumb" is 500 sq ft for every 1/2 ton, which would make our unit(s)
> more than
> workable. Is it the same rule for heating?
> Any advice so we don't get ripped off??
>
Advice?? sure.... but first, there is no such thing as a "rule of thumb"
when sizing and designing comfort systems. This is an investment that your
going to have to live with for the next 18 to 20 years. Do you really want
it based on a guess??(rule of thumb)
Call your favorite, local, *COMPETENT*(not just the lowest bidder),
licensed, insured, professionally trained, HVAC technician to correctly size
and properly design, then install your new comfort system.
FWIW, $5500 is cheap.... The rules changed on January 28, 2006. What is now
the *minimum* efficiency, had been my "premium" line for the last 5 - 7
years.
Check it out at WWW.DOE.GOV
| |
| gofish@gonefishin.net 2006-04-21, 10:21 pm |
| On 21 Apr 2006 08:12:36 -0700, "csonsini" <csonsini@gmail.com> wrote:
>We currently have a 2-1/2 ton A/C unit and a 2 ton furnace for the
>central heat/air
>in our 950 sq foot house. We received a bid for adding a 500 sq ft
>room.
>Included in that bid is $5500 for a 2nd a/c unit and furnace.
>The contractors were telling us that the unit(s) we have may not be
>sufficient for
>the total square footage that we'll end up with after the addition, and
>this unit(s) would be just for the new room. I countered by saying
>that we paid $3200 for the units that we currently have - and that's
>for our entire house...how is it possible that we'd have to pay $5500
>for 500 sq ft??? Of course, they didn't really know what to say.
>Is our current set up sufficient for less than 1400 total square
>footage? I know the "rule
>of thumb" is 500 sq ft for every 1/2 ton, which would make our unit(s)
>more than
>workable. Is it the same rule for heating?
>Any advice so we don't get ripped off??
ask your hvac contractors to submit a bid for a zoning system adding
new duct work and controls only for the new addition and connect to
existing equipment.
shit-for-brains-pjm could have told you this also......if the subject
matter wasnt over his head and out of his league.
| |
| udarrell 2006-04-21, 10:21 pm |
| csonsini wrote:
>We currently have a 2-1/2 ton A/C unit and a 2 ton furnace [?] for the
>central heat/air in our 950 sq foot house. We received a bid for
>adding a 500 sq ft room.
>Included in that bid is $5500 for a 2nd a/c unit and furnace.
>The contractors were telling us that the unit(s) we have (may not) be
>sufficient for (BULL!)
>the total square footage that we'll end up with after the addition, and
>this unit(s) would be just for the new room. I countered by saying
>that we paid $3200 for the units that we currently have - and that's
>for our entire house...how is it possible that we'd have to pay $5500
>for 500 sq ft? Of course, they didn't really know what to say.
>Is our current set up sufficient for less than 1400 total square
>footage? I know the "rule of thumb" is 500 sq ft for every 1/2 ton,
>which would make our unit(s) more than workable.
>[Forget all the Rules of thumb, it depends on many factors!]
>Is it the same rule for heating? Any advice so we don't get ripped off?
>
>
Don't fall for everything that "some contractors might tell you."
I am a retired HVAC Contractor.
Under tough conditions, I cool around 900-sq.ft. with a little
6,000-btuh room air conditioner.
Read How I do It! It does a perfect job!
http://www.udarrell.com/airconditio...h_charting.html
What state are you in and what major city are you near?
I will look up your heating and air conditions.
In most cases a properly working 2-1/2-Ton A/C with plenty of airflow
will cool a 1450-sq.ft. home.
Try using two large floor fans to circulate the air, if it appears it
will handle the heatload have Supply and Return air ductwork installed.
http://www.udarrell.com/proper_cfm_...ng_systems.html
Have a manual J, heat-gain/heat-loss done for sizing requirements and if
what you have is anywhere near without adding any oversizing percentages,
I would make it work! You can always add insulation, etc., and
supplemental portable or wall electric heating if needed on a few of the
coldest days.
Fans will keep you comfortable on the hottest days. SAVE YOUR MONEY!
- Darrell
--
Optimizing Air-Conditioner Efficiency
http://www.udarrell.com/air-conditi...rator-coil.html
| |
| aka-SBM 2006-04-22, 1:21 am |
|
"csonsini" <csonsini@gmail.com> wrote in message
news:1145637039.272141.150040@v46g2000cwv.googlegroups.com...
> Why wouldn't I post this question here??? This has to do with HVAC
> (heating/ventilation/air conditioning).
>
Then I guess I need to tell you, you dont have a 2 ton furnace...
You dont..aint possible..and if you think otherwise, you are already out of
your league.
>
> .p.jm@see_my_sig_for_address.com wrote:
>
| |
|
| Do your own heat load. It sounds like your system should
be able to handle extra 500 sq ft. Who can see from here?
Your house has insulation in the walls? Made of straw?
Located in africa? Facing E-W. Windows ? flooring?
Insulation in the attic?
| |
| Cooltemp Industries 2006-04-22, 9:21 am |
|
gofish@gonefishin.net wrote:
> ask your hvac contractors to submit a bid for a zoning system adding
> new duct work and controls only for the new addition and connect to
> existing equipment.
>
> shit-for-brains-pjm could have told you this also......if the subject
> matter wasnt over his head and out of his league.
So you want his 2 1/2 ton A/C to be wired separately and zoned to cool
500 square feet??
Ya, that'll work!
It's currently sized for aprrox. 1000 sq. ft., and he's adding half that
load again. So you want his present A/C to cool half the original load
sometimes, then cool 1 1/2 times the original load sometimes (when both
zones need cooling at the same time).
Ever heard of a Manual J ??
And we haven't even addressed the heating side of the equation yet.
Maybe you should partner up with Dido. He could be your mentor.
Talk about shit-for-brains!
| |
|
| On Sat, 22 Apr 2006 08:15:18 -0400, Cooltemp Industries
<gbroderick@sunlife.com> wrote:
>
>
>gofish@gonefishin.net wrote:
>
>
>So you want his 2 1/2 ton A/C to be wired separately and zoned to cool
>500 square feet??
>Ya, that'll work!
>It's currently sized for aprrox. 1000 sq. ft., and he's adding half that
>load again. So you want his present A/C to cool half the original load
>sometimes, then cool 1 1/2 times the original load sometimes (when both
>zones need cooling at the same time).
>Ever heard of a Manual J ??
>And we haven't even addressed the heating side of the equation yet.
>Maybe you should partner up with Dido. He could be your mentor.
>Talk about shit-for-brains!
>
Zoning is done all the time I suggest looking up by pass dampers
instead of ragging about something you dont seem to know about.
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