Home Page link

Is this new HVAC system performance acceptable?

Home| Search | About
Login Password
Register Now! Lost Password?

HVAC Discussions - Heating, ventilation and air conditioning. 

Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Is this new HVAC system performance acceptable? ejohnson10 08-09-2007
If you were  Registered and logged in, you could reply and use other advanced thread options
Posted by on August 9, 2007, 12:28 pm
I just had a new HVAC system installed in a new house and it has been
running for about two months. I haver not fully paid for the system yet as
the contractor still has some work left to do (load balance & cosmetic
stuff).

Today the temperature is 100 outside. I have my thermostat set to 77 and
the actual temperature is 81. (This is upstairs, downstairs a separate
system is maintaining the selected temperature.)

I am getting about a 20 degree drop. The contractor tells me that this is
normal performance and I should not expect more than a 20 degree drop.

Is that acceptable as an industry standard for residential systems, or
should the system be doing better? Should I accept the system as-is or
demand better performance?

In my location 95-102 degree days occur every summer but it is rare to have
more than 10-15 of them per year. I would rather have a slightly
undersized system than an oversized one.

Thanks for any help!

Posted by on August 9, 2007, 12:52 pm
On Thu, 09 Aug 2007 12:28:51 -0400, ejohnson10@charter.net wrote:

>I just had a new HVAC system installed in a new house and it has been
>running for about two months. I haver not fully paid for the system yet as
>the contractor still has some work left to do (load balance & cosmetic
>stuff).
>
>Today the temperature is 100 outside. I have my thermostat set to 77 and
>the actual temperature is 81. (This is upstairs, downstairs a separate
>system is maintaining the selected temperature.)
>
>I am getting about a 20 degree drop. The contractor tells me that this is
>normal performance and I should not expect more than a 20 degree drop.
>
>Is that acceptable as an industry standard for residential systems, or
>should the system be doing better? Should I accept the system as-is or
>demand better performance?
>
>In my location 95-102 degree days occur every summer but it is rare to have
>more than 10-15 of them per year. I would rather have a slightly
>undersized system than an oversized one.
>
>Thanks for any help!

Your contractor is lying to you. You need a 45 degree drop. You
probably have one of those digital thermostats installed, those things
are notorious for only having a 20 degree drop when they are installed
in upstairs applications. I'd call them and tell them you want a 45
degree drop and you are going to withold the balance do until they fix
it.

Posted by on August 9, 2007, 1:02 pm
On Thu, 09 Aug 2007 12:28:51 -0400, ejohnson10@charter.net wrote:

>I just had a new HVAC system installed in a new house and it has been
>running for about two months. I haver not fully paid for the system yet as
>the contractor still has some work left to do (load balance & cosmetic
>stuff).
>
>Today the temperature is 100 outside. I have my thermostat set to 77 and
>the actual temperature is 81. (This is upstairs, downstairs a separate
>system is maintaining the selected temperature.)
>
>I am getting about a 20 degree drop. The contractor tells me that this is
>normal performance and I should not expect more than a 20 degree drop.
>
>Is that acceptable as an industry standard for residential systems, or

        Yes

>should the system be doing better? Should I accept the system as-is or
>demand better performance?
>
>In my location 95-102 degree days occur every summer but it is rare to have
>more than 10-15 of them per year. I would rather have a slightly
>undersized system than an oversized one.

        Then you have what you want.

>
>Thanks for any help!

--
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/

Posted by udarrell on August 9, 2007, 1:48 pm
ejohnson10@charter.net wrote:

>I just had a new HVAC system installed in a new house and it has been
>running for about two months. I have not fully paid for the system yet as
>the contractor still has some work left to do (load balance & cosmetic
>stuff).
>
>Today the temperature is 100 outside. I have my thermostat set to 77 and
>the actual temperature is 81. (This is upstairs, downstairs a separate
>system is maintaining the selected temperature.)
>
>I am getting about a 20 degree drop. The contractor tells me that this is
>normal performance and I should not expect more than a 20 degree drop.
>
>Is that acceptable as an industry standard for residential systems, or
>should the system be doing better? Should I accept the system as-is or
>demand better performance?
>
>In my location 95-102 degree days occur every summer but it is rare to have
>more than 10-15 of them per year. I would rather have a slightly
>undersized system than an oversized one.
>Thanks for any help!
>
>
If it has low airflow or a very low latent heat load (humidity) the temp
drop can be rather meaningless.
The evaporator may not have enough airflow through it, which throws
charging the refrigerant system off, which compromises performance.

That temp drop can vary from 14 to 26-F & still be within tolerances.
What is the % of Relative Humidity in your home. (Get a Humidity gauge
at a good hardware store!)

Take the air discharge temp split of the outdoor condenser & list the
SEER Rating & tonnage of the condenser.
Provide all that data here, which will only provide us some clues & not
a bullseye diagnosis.
http://www.udarrell.com/air-conditioning-total-heat-enthalpy-latent-heat.html

- udarrell

--
WISDOM PRINCIPLE DIRECTED EMPOWERMENT COMMUNICATIONS -
THE REAL POLITICAL ISSUES and WISDOM BASED PEOPLE EMPOWERMENT

http://www.udarrell.com/

http://www.udarrell.com/my_pages2.htm
(My Airconditioning Links, Hunting Shooting, Angus Cattle, etc.)

http://www.udarrell.com/principled_adjudication_disputes_administration_justice.html

http://www.udarrell.com/recognizing_real_enemies.html

http://jesuschristsavior.net/Beatitudes.html

http://www.antiwar.com/ ***

Reality Is Not An Easy Thing To Be Confronted With, or to Accept!

Posted by on August 9, 2007, 2:27 pm
Thanks. I will do what you suggest, however in one sense the SEER and
tonnage rating do not matter to me as far as determining if the contractor
did an acceptable job. Part of his job was to design the system. We
agreed on a SEER rating and he selected the tonnages he felt would do the
job. He was to design a system that would properly heat & cool the house
and he chose all of the equipment, designed the ducts (vent & return),
selected the thermostats, etc.

I will say that the air flow seems quite high out of the vents so there
must be a lot of air going through the evaporator. The compressors are in
the sun. (Would it help to provide share for them?)

(Note: I accidentally started this thread using a real email address.
However, it is one I have never used and will not use so I don't check it.)

wrote:

>ejohnson10@charter.net wrote:
>
>>I just had a new HVAC system installed in a new house and it has been
>>running for about two months. I have not fully paid for the system yet as
>>the contractor still has some work left to do (load balance & cosmetic
>>stuff).
>>
>>Today the temperature is 100 outside. I have my thermostat set to 77 and
>>the actual temperature is 81. (This is upstairs, downstairs a separate
>>system is maintaining the selected temperature.)
>>
>>I am getting about a 20 degree drop. The contractor tells me that this is
>>normal performance and I should not expect more than a 20 degree drop.
>>
>>Is that acceptable as an industry standard for residential systems, or
>>should the system be doing better? Should I accept the system as-is or
>>demand better performance?
>>
>>In my location 95-102 degree days occur every summer but it is rare to have
>>more than 10-15 of them per year. I would rather have a slightly
>>undersized system than an oversized one.
>>Thanks for any help!
>>
>>
>If it has low airflow or a very low latent heat load (humidity) the temp
>drop can be rather meaningless.
>The evaporator may not have enough airflow through it, which throws
>charging the refrigerant system off, which compromises performance.
>
>That temp drop can vary from 14 to 26-F & still be within tolerances.
>What is the % of Relative Humidity in your home. (Get a Humidity gauge
>at a good hardware store!)
>
>Take the air discharge temp split of the outdoor condenser & list the
>SEER Rating & tonnage of the condenser.
>Provide all that data here, which will only provide us some clues & not
>a bullseye diagnosis.
>http://www.udarrell.com/air-conditioning-total-heat-enthalpy-latent-heat.html
>
>- udarrell


Similar ThreadsPosted
replace hvac system question July 10, 2006, 6:22 pm
HVAC Timers - How do we cut off the system only during church each Sunday? December 31, 2007, 10:38 am
Winter condensation problem in HVAC duct system January 28, 2008, 10:42 am
Keeprite performance August 25, 2007, 9:26 am
Which Carrier gas furnace: Performance 80 or 93 ? April 25, 2008, 10:01 pm
Trane TWR030C heat pump, poor performance.. October 31, 2006, 5:59 pm
Trane TWR030C heat pump, poor performance.. October 31, 2006, 6:05 pm
Re: Intermittent high pressure in hot water heating system system February 3, 2007, 9:46 am
Re: Intermittent high pressure in hot water heating system system February 4, 2007, 3:49 pm
Re: Intermittent high pressure in hot water heating system system February 4, 2007, 3:54 pm

Contact Us | Privacy Policy

XML SitemapXML Sitemap