Gas Furnace vs. Heat Pump in Portland, OR

[oldpdx]

I'm replacing a 20+ yr old gas furnace in a 100 yr old "leaky" house in Portland, Oregon where the avg winter low temps are in the mid 30's, a week or two in the 20's. We also have 2-3 weeks of 90+ degree heat in the summer where cool air would be nice (we currently have no central AC). I'm having trouble getting a firm rationale for going with a nice high efficiency gas furnace with central AC unit vs high eff heat pump with gas furnace back up.
I've had a couple of estimates from Carrier dealers, one Trane and one Lennox. The Trane dealer is the only one who thought the heat pump would be a good idea in our area (he loves his heat pump). I haven't heard too many arguments from the other guys about why the heat pump wouldn't be good here other than the gas furnace as your work horse will last 20+ years, whereas heat pumps last about 12 yrs on average (from the lennox guy). I have heard also heat pumps are more complicated to install so things can go wrong if not done well, the air feels cooler (which may generate more service calls or complaints), utility bill will go up a lot (but utilities are cheap here and have been stable over my 4 yrs here, gas has gone up twice).
Any strong opinions about life span of new high eff gas furnace vs heat pumps?
Any clear concensus on which brand (Carrier, Trane, Lennox) makes the most reliable gas furnace or heat pump?
Lets assume each dealer is equally reputable with installation and service. I'm also not that concerned with the economic pay-off as I am with reliability and performance.

[DeltaT]

The PNW is a great place for heat pumps. I'd spend some money first unleaking the old house and adding new window and/or insulation first. Rheem is my favorite. Quality made, anyone can work on them. They don't cost a fortune and you don't necessarily have to get involved with a "dealer" network, which typically means highers costs.

[nwgasman]

In our area, (PDX) I'm of the opinion if you are buying for economics and don't feel you need to spend extra $$ for cooling I don't recommend HP's.

There are added tune up costs associated with HP's and we usually don't see exceptional savings with electrical heating systems given the extra costs with maintenance.

If cooling is required a hi-eff gas furnace, (like the Infinity) paired with a 13 SEER A/C can be a better value if you feel you won't be in the home over 6-7years.

We also have homeowners that are not happy with the quality of heat produced by Hp's as their temps are often lower at the register than gas heat... HP's can feel a bit drafty when compared to the hotter heat produced by furnaces.

Bottom line, you should choose the company based on quality and professionalism and focus less on the brand name. Have you visited any of the HVAC businesses you are concidering? Are they well established with fully staffed depts. and showrooms? Do they offer 100% satisfaction gaurantees?

Hope that helps.

[zootjeff]

Hey, it's been two years, what did you wind up going with?

I got a heatpump and I love it. I made a spreadsheet to compare the cost between Portland General and NW Natural Gas and I save money 6 months out of the year using my 14Seer heat pump for heating. I found that the bottom line utility costs were:

Heat pump costs: $0.023 to $0.029 per kWH heating (depending on outdoor temp)
Gas furnace costs: constant $0.042 per kWH heating (converted from therms)

So between 1.9x and 1.5x less utility costs to run the HP.

This was based on NW Natural and Portland General Electric rates of $1.43 per therm (gas) and $0.102 per KWh (electric) AND I have a 92% efficient Trane Gas furnace for backup heat.

I'm curious about the costs to keep a heat pump serviced being higher than costs to keep a AC unit serviced? I don't understand why it would cost any more to maintain a HP vs an AC unit? Can some one explain this to me? Is it because reversing valves fail constantly? Is it because TXVs die left and right? I thought the only real difference was the upfront costs..

I'm not going to be complaining about the 95-110 degree heat coming from my heatpump air and making a service call. I think that is bogus. It's plenty warm when I stand near a register.

[skippedover]

There are added tune up costs associated with HP's and we usually don't see exceptional savings with electrical heating systems given the extra costs with maintenance.

Any added tune-up costs should be minimal. If you've got a gas furnace w/AC on it, where's the additiona cost? He said he's like to have a new furnace w/AC so he can either add the AC as an expense and gain some comfort or he can add a HP, get the AC included and turn the expense into an investment. With temps like he's quoting, unless the electric rates are exhorbitent and the gas very, very cheap, he'll save with a HP. And if he doesn't save, he can always turn it off! But at least he's got the option. With a straight AC, the only option is on or off.


If cooling is required a hi-eff gas furnace, (like the Infinity) paired with a 13 SEER A/C can be a better value if you feel you won't be in the home over 6-7years.

With temps mostly 30 or above, the gas furnace certainly doesn't work much. Depending on the elctric and gas rates, I think he'd be more efficient with a high efficiency HP and a basic 80% gas furnace, given the little use the furnace will get. The HP will be used almost all the time. I'm in Massachusetts and use my HP down to 35F quite economically. And our electric rate is $0.18/kwh.


We also have homeowners that are not happy with the quality of heat produced by Hp's as their temps are often lower at the register than gas heat... HP's can feel a bit drafty when compared to the hotter heat produced by furnaces.

This is due to the duct design. A duct system installed for a HP should be larger than one installed for a gas furnace. That's to allow the airflow to slow somewhat so the air is in contact with the indoor coil longer, warming to a higher temp. Also, since he's going to be using the HP at fairly warm OATs, in the HP mode the evaporator will be warmer, in turn raising the condensing temperature, which equals a warmer airflow. We do dual fuel systems regularly and I've never fielded a call for unsatisfactory temperatures.


Bottom line, you should choose the company based on quality and professionalism and focus less on the brand name.

I couldn't agree more with that statement!!


Have you visited any of the HVAC businesses you are concidering? Are they well established with fully staffed depts. and showrooms? Do they offer 100% satisfaction gaurantees?

Unfortunately, I couldn't disagree more with that statement!! Since when does a showroom make for a good system design? I know of companies around our area who are so big, they can't train anybody to do decent work. They have a showroom but their work is truly hack. You're right that the company that installs the system makes it a wonderful experience or purely agonizing but whether that's a highly experienced single person with helper or a flotilla of trucks and showrooms makes no difference. Read my attached and then decide.

[SkyHeating]

I just ran across this post also. I would say heat pump all the way but then again I wonder if I am the Trane Dealer the OP spoke up since I sell Trane and do LOVE my heat pump in my house. My most expensive gas bill was $43 for a 1600 sq foot house and my electric was only slightly higher than the year before.

Tune up costs are only $20 more for a heat pump through my company which is more than saved in only a single month with the heat pump. If you havn't selected a system yet or if you still have questions feel free to give us a call in portland at 503-235-9083 and we can answer any questions even if you dont' want another bid.

-Travis

[scouser57]

I'm replacing an antique, gas, gravity octopus furnace. I've had several HVAC companies come in to give me bids. Now I'm totally confused on what type of system to go with (HP vs. gas furnace) and winter's coming! I have a 1924 950 sq ft two-bedroom bungalow. One company suggested placing a Mitsubishi SUZ-KA18NA indoor air handler in the attic with the Mitsubishi Model SEZ-KD18NA outdoor unit. This would require ceiling registers be installed (I currently have floor registers). Another HVAC company said HP's are noisy and wouldn't suggest cutting into my ceiling to put in registers. I like the idea of A/C, so in either case would want that option. I currently pay $91 per month year round on my gas bill with the old gravity furnace. Would appreciate any words of wisdom. Have to make a decision within the next week. Thanks everyone!

[TxTurbo]

If you have an existing duct system, why would you put in a mini-split? Adding an AC or HP would be much easier to add to your existing furnace. Heat pumps are just as quiet as an AC system. Actually it uses the same components.

Has anyone performed a Manual-J heat load calculation on the house yet?

We service the Portland metro area, my email is in my profile if you'd like me to come out and take a look.

[seatonheating]

If you have an existing duct system, why would you put in a mini-split? Adding an AC or HP would be much easier to add to your existing furnace. Heat pumps are just as quiet as an AC system. Actually it uses the same components.

Has anyone performed a Manual-J heat load calculation on the house yet?

We service the Portland metro area, my email is in my profile if you'd like me to come out and take a look.

Hopefully you received an email TX.


I think the Mitsubishi that is spoke of is the ducted system.

[SkyHeating]

My company works in the Portland area, we have been in business over 30 years, have NATE certified technicians and can take a look at the full picture of heating and cooling your house. I can see why someone would say maybe the mitsubishi would be a better option for the price it will take care of heating and cooling as a heat pump can probably not be added to your existing gravity furnace and replacing your furnace with a new furnace and AC would be more expensive than a mitsubishi unit. Also with many gravity furnaces in the portland area there really isn't much for "ductwork" in the house, usually just one large return air sized opening so the mitsubishi unit could take care of all that is needed. Our website is my username and my e-mail is there. We can communicate that way and setup an appointment if you like. I am the owner of the company and will make sure we properly take care of your situation.

Travis Smith
Sky Heating - Owner


I'm replacing an antique, gas, gravity octopus furnace. I've had several HVAC companies come in to give me bids. Now I'm totally confused on what type of system to go with (HP vs. gas furnace) and winter's coming! I have a 1924 950 sq ft two-bedroom bungalow. One company suggested placing a Mitsubishi SUZ-KA18NA indoor air handler in the attic with the Mitsubishi Model SEZ-KD18NA outdoor unit. This would require ceiling registers be installed (I currently have floor registers). Another HVAC company said HP's are noisy and wouldn't suggest cutting into my ceiling to put in registers. I like the idea of A/C, so in either case would want that option. I currently pay $91 per month year round on my gas bill with the old gravity furnace. Would appreciate any words of wisdom. Have to make a decision within the next week. Thanks everyone!

[scouser57]

I should add that the current ducts are asbestos-wrapped and I'm having them removed. The old octopus gravity furnace is also asbestos-wrapped and takes up 2/3 of my small basement. Are you thinking that my current furnace could be a "back up" to a HP? It's not energy-efficient at all.
I haven't heard the term "Manual-J heat load calculation" used by anyone, but did have an energy audit done by the Energy Trust of OR.
And, yes, I believe the Mitsubishi HP is a ducted system. I don't know if there is an advantage to having an outdoor HP vs. an "inside" (attic) HP.
Also looking to utilize current rebates and tax incentives ~ Thanks all!

[beenthere]

This is due to the duct design. A duct system installed for a HP should be larger than one installed for a gas furnace. That's to allow the airflow to slow somewhat so the air is in contact with the indoor coil longer, warming to a higher temp.

A larger duct size would actually decrease the amount of time the air was in contact with the coil. Since it allows for more air flow.

[martyinlincoln]

I should add that the current ducts are asbestos-wrapped and I'm having them removed. The old octopus gravity furnace is also asbestos-wrapped and takes up 2/3 of my small basement. Are you thinking that my current furnace could be a "back up" to a HP? It's not energy-efficient at all.
I haven't heard the term "Manual-J heat load calculation" used by anyone, but did have an energy audit done by the Energy Trust of OR.
And, yes, I believe the Mitsubishi HP is a ducted system. I don't know if there is an advantage to having an outdoor HP vs. an "inside" (attic) HP.
Also looking to utilize current rebates and tax incentives ~ Thanks all!
No, don't use that old furnace as a back up. Replace it and the octo duct work. Probably no manual J done because you wont need anything but the smallest BTU system with 950 square foot. Two stage equiptment costs a bit more but will give you the greatest comfort making it a great value.
IMO you're better off with the new duct work, furnace and coil in the basement rather then the attic. Always best to keep the duct in the conditioned space when possible.

[ga-hvac-tech]

I would do the HP/gas backup... called DualFuel system if it were my home. I have this arrangement at my home and it both works well and saves some energy. I recouped my investment (DF vs gas/AC) in less than 2 years and enjoy the 'soft' feel of HP warmth... as opposed to a blast of HOT air... on mild nights.

On the service side: IMO a HP needs to be cleaned and serviced AT LEAST once a year... better to do spring and fall service. A dirty unit both uses more energy as well as shortening its life.

There are more controls and details to a HP system, choose a contractor that is 'detail oriented' and will take care of the system.

And IMO it would be wise to read around here at H-talk about installation. Installation is the key... brand is secondary.

[TxTurbo]

I should add that the current ducts are asbestos-wrapped and I'm having them removed. The old octopus gravity furnace is also asbestos-wrapped and takes up 2/3 of my small basement. Are you thinking that my current furnace could be a "back up" to a HP? It's not energy-efficient at all.
I haven't heard the term "Manual-J heat load calculation" used by anyone, but did have an energy audit done by the Energy Trust of OR.
And, yes, I believe the Mitsubishi HP is a ducted system. I don't know if there is an advantage to having an outdoor HP vs. an "inside" (attic) HP.
Also looking to utilize current rebates and tax incentives ~ Thanks all!

Ah, if you're getting rid of the existing duct system, that would explain the suggestion of a mini-split and does make sense in your situation.

A heat pump system will have both outdoor and indoor components. A condensing unit outside to collect heat and a 'fan coil' or 'air handler' inside to dump the collected heat into your home.

I would need to see the layout of the house, but I generally try to stay away from the ducted mini-splits because they don't heat that well below 30F outside. Some of the wall-mounted systems will produce full heat down to -13F.

A heat load should always be run on the home, especially when installing a new system with ductwork. It tells us the air flow needs of each room, helps us decide optimal placement of the vents and determine the best unit size.

Similar to Sky Heating (another great company in the area) our techs are NATE certified. We also perform all of our installs to the ACCA/Energy Star Quality Installation standard. As as added bonus we also take care of all the complicated rebate and tax credit paperwork for you.

[speedymonk]

I think the heat pump NG furnace backup is a no-brainer in this part of the country. Hope the OP fixed his building envelope and windows first. The old pay me now or pay me later deal.

Flexibility is great with an HP system and NG backup. Provided the system is sized right-- including the ducts-- the system should last at least 20 years. I'm getting new returns installed even though it is a new house (3.5 years old). Contractor installed a single 12 inch cold air return when an 18 inch should have been installed.

Also putting in a second return downstairs. No more jet engine noises and better breathing and life expectancy for the system. Wallet will be a little thinner. The HVAC contractor cut corners. I thought there was a problem but couldn't get anybody to verify until I hired this fellow's maintenance company (Trane dealer) to look at the situation.

Sorry for the bunny trail.

[fuzz_factor]

Hi all,

I'm buying a house in Portland, OR and have the home inspection scheduled for tomorrow.

The house has a Trane Electric heat pump. Well, at least the exterior unit is a Trane...I assume that interior unit is the same. I'm already a bit concerned that the HP is old and perhaps under-powered for the house.

What questions should I ask and what should I watch out for? Since I'm still in the inspection phase, I have some negotiating power and time to back out of the deal.

All appliances are electric and there is no gas line run to the house (unless it's capped). I don't think there is a backup heat source unless it's internal to the HP itself. In any case, it will also be electric. There is a fireplace with a newer wood stove. And, come to think of it, plenty of wood in the yard...

I apologize for my ignorance, I don't know the model number of the HP and I think it's around 11 years old. IIRC, installation was in '99. I don't know when it was last serviced. The house has floor registers and the ducting actually looked fairly small. It was round duct work, not the huge square stuff I've seen in houses with newer gas furnaces.

After reading this thread, I'll certainly take a close look at the model, specs, service history, and anything else you guys recommend.

Thanks for any help!

[DeltaT]

Consider a HVAC contractor who has a great deal of experience with heat pumps to do a separate inspection.

[seatonheating]

Consider a HVAC contractor who has a great deal of experience with heat pumps to do a separate inspection.

He should call TXTurbo's company. I know him and his company. They are true professionals.

[DeltaT]

He should call TXTurbo's company. I know him and his company. They are true professionals.

You should tell him that. :CU:

[fuzz_factor]

Hey all: The Heat Pump referenced below is a Trane TWE030C. I couldn't find the SEER, COP or HSPF numbers online or in the unit's manual. The unit was installed in '99 and although there was a recent servicing, there wasn't a service history attached to the unit.

If anyone has rough guesses on how long this sucker might last or how well it will work in a roughly 2000 SF house (about 1200 SF upstairs, the rest basement), I'd sure appreciate your opinions.

EDIT: Oh yeah, I think the exterior part of the heat pump was a Trane XL1100.

Thanks!

[seatonheating]

Hey all: The Heat Pump referenced below is a Trane TWE030C. I couldn't find the SEER, COP or HSPF numbers online or in the unit's manual. The unit was installed in '99 and although there was a recent servicing, there wasn't a service history attached to the unit.

If anyone has rough guesses on how long this sucker might last or how well it will work in a roughly 2000 SF house (about 1200 SF upstairs, the rest basement), I'd sure appreciate your opinions.

EDIT: Oh yeah, I think the exterior part of the heat pump was a Trane XL1100.

Thanks!


All you will get from us here is uneducated opinions because we haven't physically seen it or laid our hands on it. Call the man I referenced you to.

[TxTurbo]

Give me a call or shoot me an email (both are in my profile). I would be happy to drop by and evaluate the current system for no charge. It's a service we offer to home sellers and buyers in the Portland area.

(thanks for the reference seaton!)

[fuzz_factor]

Give me a call or shoot me an email (both are in my profile). I would be happy to drop by and evaluate the current system for no charge. It's a service we offer to home sellers and buyers in the Portland area.

(thanks for the reference seaton!)

Cool! Thanks!

[Cumberland]

I'm replacing a 20+ yr old gas furnace in a 100 yr old "leaky" house in Portland, Oregon where the avg winter low temps are in the mid 30's, a week or two in the 20's. We also have 2-3 weeks of 90+ degree heat in the summer where cool air would be nice (we currently have no central AC). I'm having trouble getting a firm rationale for going with a nice high efficiency gas furnace with central AC unit vs high eff heat pump with gas furnace back up.
I've had a couple of estimates from Carrier dealers, one Trane and one Lennox. The Trane dealer is the only one who thought the heat pump would be a good idea in our area (he loves his heat pump). I haven't heard too many arguments from the other guys about why the heat pump wouldn't be good here other than the gas furnace as your work horse will last 20+ years, whereas heat pumps last about 12 yrs on average (from the lennox guy). I have heard also heat pumps are more complicated to install so things can go wrong if not done well, the air feels cooler (which may generate more service calls or complaints), utility bill will go up a lot (but utilities are cheap here and have been stable over my 4 yrs here, gas has gone up twice).
Any strong opinions about life span of new high eff gas furnace vs heat pumps?
Any clear concensus on which brand (Carrier, Trane, Lennox) makes the most reliable gas furnace or heat pump?
Lets assume each dealer is equally reputable with installation and service. I'm also not that concerned with the economic pay-off as I am with reliability and performance.
I'm replacing a 13-year-old furnace and A/C, and have two different bids. One would replace with a combination of ducted and ductless HP, ducting through the ceiling. The other was to combine a HP and gas back-up, and vent through the floor. Since my home is completely torn apart, I can do either, or anything else. But (1) do I need a back-up to a HP in Portland, OR, and (2) do I need to have floor heat supply lines for comfort, or will ceiling supplies give me a even temperature in my large home (about 2,800 sf on the first floor, with lots of windows, which are going to be replaced with isulated panes of at least U = 0.29)?

[beenthere]

Rmarshall, this is the Ask Our Pro's forum, and only Pro members that have been vetted by the AOPC may post advise here. Please apply to the AOPC today, thank you.

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