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Which option for a 130 year old brick house.

Posted by mikensx (mikensx@comcast.net) on
Fri, Sep 28, 12 at 9:57

2 1/2 story plaster on brick house. 32 large windows replaced with low e double pane. 3,500 sq of heated area.

I want to replace my 22 year old HVAC system with an efficient setup. Currently have natural gas 190,000 btu furnace about 68% efficient and 5 ton AC. The AC unit is sized too large and runs about 60% on the hottest days. On not so hot days, the house is cool but clamy. It costs about $600/mo to heat and $400 to cool. My duct work is not set up for cooling; all air returns on first floor, but it works for me. I have ceiling fans to move air. About a 4 degree difference from 1st to 2nd floor.

My installer said that efficiency is so much higher now then my equipment that my savings will be significant. I'm thinking a condensing furnace in the low 90% range, and a high seer AC unit.

Today, he suggested that for a thousand more he thinks that I should consider a high efficiency heat pump with gas back up. He's telling me that these heat pumps today can work down into the low teens with good efficiency.

But, I've heard that heat pump houses often don't feel warm. And my house in hard to heat with ice cold walls.

My goal is to raise efficiency and realize real savings on monthly bills while not spending a huge amount on the equipment.

I see there is a great price difference between high efficiency and the latest super high efficiency. I don't want to double my equipment cost to gain 6%.

What do you think? is heat pump a good choice for an old brick low efficiency house?

Thanks


Follow-Up Postings:

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RE: Which option for a 130 year old brick house.

dual fuel is sweet. but if you
are used to gas heat, the heat from the
hp is cooler. it may be better that you
stay with gas as primary heat.

90+% furnaces are worth every penny in my
experience..and I'm in a cooling climate.
why waste $$ & put a combustion appliance when
you can take advantage of more efficiency.

same for a/c side. 13 SEER is minimum produced
efficiency equipment. to upgrade to 15-17 SEER makes
economic sense. beyond 17 SEER is not as good of use
of money. for example Trane has i series..20i
is not 20 SEER. so check actual efficiency of equipment
and what it is paired with. mismatched equipment
delivers lower efficiency. ARI information for
matched equipment should be provided by hvac company.
or go online yourself & verify...before purchase & install.

also in older homes insultion may or may not be present.
to first air seal house for leaks, and air seal ducts
for leaks is the best investment you can make.
blower door testing of house, and testing ducts
for leakage may cost you a few bucks, but sealing
these areas save you every month. caulks and mastics
are cheap, but work very well.

you say:
The AC unit is sized too large and runs about 60% on the hottest days. On not so hot days, the house is cool but clamy. It costs about $600/mo to heat and $400 to cool. My duct work is not set up for cooling; all air returns on first floor, but it works for me. I have ceiling fans to move air. About a 4 degree difference from 1st to 2nd floor."

in cooling climates we want long run times. this allows the equipment to remove humidity..which sounds like your issue.
an evaluation of the ductwork as you say it was designed for heating would be recommended. new unit will be more efficient & remove more humidity, but you need to have ductwork that doesn't add to humidity load. same as leakage
of house. both can contribute to RH in the house.

whole house dehumidifiers work well, or a stand alone
dehumidifier. if RH is a problem, invest in stand alone
and see how that works for you before investing in
whole house system.

best of luck.


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RE: Which option for a 130 year old brick house.

1st installer came out to chat with me. He would not recommend heat pump/gas because of the low cost of natural gas.

1. He recommends AC plus high efficiency gas furnace.
2. He recommends media filter, not electronic air cleaner.
3. He does not recommend an in-line humidifier. Says they leak and rust out furnace.
4. When I brought up cleaning the old duct work, he recommends replacing the metal duct work with modern fiber glass.

Does all this sound reasonable?


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RE: Which option for a 130 year old brick house.

1-3 sound very reasonable and right on. I don't know enough about #4.


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RE: Which option for a 130 year old brick house.

What should I expect to pay for replacement equipment.

My present system was installed in 1991. It is Rheem low efficiency 175,000 BTU furnace and 5 ton AC. I paid $5200 in 91. It connects to existing ductwork.

I am now looking to replace it with a high efficiency furnace and AC unit. What should I expect to pay?


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RE: Which option for a 130 year old brick house.

It is difficutl to estimate a price without knowing the sizes and difficulty of the installation. You seem to be very oversized, but a 130 year old house may have poor insulation and leaky windows. The high efficiency furnace must exhaust out the side of the house. Is this going to be problem with a brick structure? You may also have to reline your chimney if you are using a gas hot water heater.

I would think a price of $10-12K is reasonable, but it could be vary depending on the factors listed above.


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RE: Which option for a 130 year old brick house.

the ductwork should be evaluated.
if set up is hard pipe ducts sized for heating
they may not work well for ac as it has
higher velocity.

the high utility costs may be in part hvac
inefficiency, but air leakage in 130 year
old houses should be consitered.

here in the south balloon framing was popular
for natural cooling. adding forced air system
to this type of house changes the whole dynamic
of the structure.

sealing, insulating & correctly sizing ducts
would be a part of the hvac size choice.

best of luck.


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