Having just been thoroughly chastised at alt.hvac, sometimes I just love the
Net Police, it was suggested that I post my question here. To add a bit
more context, I have been searching Google for a few days now and have not
really found much that is definitive. I am trying to understand the
technology from the point of view of a consumer, not a system designer, and
to become educated enough to determine if the contractor/consultants we deal
with are worth a hill of beans :-). My field is Software Development, and I
can assure you that every good consultant/company there are 100 hacks that
will take your money and give little value. My experience is that this is
common across all fields and that quite often system failures are a result
of not knowing enough to ensure that you get one of the "good ones".
We are awaiting completion of a new home in the Marysville area of
Washington, about 30 miles North of Seattle. I am considering speaking with
the builder about putting in a heat pump rather than a conventional gas
furnace. We don't often get temperature extremes in this area, a few weeks
of sub-30 degrees in the winter is a cold one and a few weeks of +80 is the
summer is a warm on, although you would be hard pressed to believe the
latter had you been here the past of couple of weeks :-).
I don't know much about heat pumps, other than the "big bits" sit outside.
What is the feeling about this being cost effective in this climate and what
should I look/ask for? If we do go with a heat pump, should we be asking
for any changes in the standard duct work regarding placement? Our
alternative is to add a couple of ceiling fans for cooling and circulation
along with a conventional gas furnace.
Please make the assumption that I don't even know the right questions to ask
of the group and help educate me. This statement got me reamed on alt.hvac
for "being lazy". What this is is an acknowledgement that the professionals
in this area know a lot more than I do, and any tips that I can get to vet a
good installer/contractor will certainly help. Ideally would be to find
someone in the area via this NG that I could do business with. Not that I
don't trust the builder, but I don't even trust myself :-).
Thanks in advance, much appreciated.
Nice to see you made it here!! :-)
To start with answering your questions....
Anybody that wants to install a system in your home needs to start with a
Manual J & D.
This will insure they size the units properly for your particular home.
Manual D, will insure that the duct system is adequate for the size of
After that, they need to qualify your particular needs.....
Air filtrations needs....do you need better filtration due to allergies?
Humidification....due to cold dry weather conditions.
System noise, are you concerned with system noise?
Temperature swings.....etc, etc....
Then after they know your needs, they can set up a system that will perform
well to your particular requirements
Heat Pumps really don't work well in area's where the ambient temps drop
below 32 degrees.
Also, HP will require larger ductwork for them to operate efficiently.
I would look into getting the highest efficiency gas fired furnace you can
Find the best installer you can find. The installer is more important then
the name on the equipment.
Your buying quality that the contractor is providing for you. This is
something you will use for years to come, so don't skimp on the initial
Doing it right the first time is a must, as it will cost BIG dollars to fix
any mistakes later down the road.
Also remember your comfort relies on the contractor you choose, so make a
sound decision on quality and not a 'low bidder' syndrome.
(my old drivel snipped, you can read it in the thread if you care...)>
Thanks for the civility and for following me here to help.
OK, most of that I have seen elsewhere on the Web, at least the references,
execpt for the tips on "particular needs", that is good info to keep in
I have seen reference to this several times, and it is one of the reasons
that I wonder if this is the right climate. Given that we don't get many
days/weeks of sub-32, would the heat-pump still be a good idea? Is this why
you suggest still having a high-efficiency gas fired furnace as well, for
those days that are below 32? From what I have been reading, mostly
manufacturers sites which is always hazardous :-), I thought that the heat
pump replaced the furnace and added AC for "free" (yeah, right).
I suspected as much, which is why I want to understand some of this before
they get too far in the build process.
Now THIS is the real crux of the issue, isn't it? How does one ensure that
the contractor really has a clue? Always tough, even when you get good
From what you have said here, and a few other bits I have found, I am
wondering if a Heat Pump is really the best solution, of if I should just
stick with a gas furnace and supplement with ceiling fans, which was my
first thought. Is there a "generally accepted" temperature range/climate
where heat pump technology by itself is best suited? It sounds as if the
floor is at 32-35 F for air-to-air (right terminology?) and a bit lower for
ground-source(again, correct terminology)?
By the way, one thing you said above that really hits is the "high
efficiency" furnace. That is one thing we should look into regardless of
what we do, as I am pretty darned sure the "builder standard" is somewhat on
the mediocre side :-).
Well, my next endeavor will be to ask about tankless "instant-on" water
heaters, who knows where that will go :-).
Thanks a bunch, kjpro, much appreciated.
Nothing is free.....it's the quality of the purchase that matters.
(you can pay now for a quality install, or pay more in the long run!!)
In an area, where the temps drop to a low and the HP can not produce the
require btu to heat your home it has electric back up strips to supplement
This is where you could end up paying high energy cost compared to running a
high efficient furnace.
The builders in our area normally install 80% furnaces, which is completely
insane. I haven't install an 80% for quite some time now. If you install a
high efficiency furnace like 92%, you save 12 percent of the energy you
input into the furnace. So take easy figures $1000 in fuel cost per year
with a 80% furnace....$800 stays in you home as the other $200 goes right
Now on the other hand the 92% is only going to input $870 to get the same
$800 worth of heat, saving you $130 per year. At 1300 per 10 years. Now you
have to figure out how long you are going to be in the home. (10-20 years? $1300-2600)
While the cost difference in the initial install could be as low as $500,
saving you some MAJOR cash.
Also, you may want to invest in a two-stage gas fired furnace to save even
As it will fire on a low setting in low load conditions and fire on high
when it's -30 outside.
Remember the longer the furnace runs, the better efficiency and filtration
you are getting.
(compare it to your car, 'longer trips' better fuel mileage)
No no nooo......Im flattered, but Im a just a homeowner and semi retired
aerospace machinist turned machine shop owner who happens to have been
cursed from birth with an intense curiosity about how mechanical things
I only know enough about hvac to get by mostly for myself, and I never done
it as a professional in my life.......
Much of what I have learned most recently about hvac is through mainly
lurking and listening to the real pros such as yourself and several others
over in alt.havoc, where over time most of the regulars have gotten to where
they at least tolerate my occasional....errrr...."contribution".......
Well, shit man....you have more intelligence then the 'Davey/Stormin' type
of so called pro's! LOL
This clears up some of the things I see you post, I just say to myself "wtf
is he saying"! :-)
OK, are you guys finished with the "back patting" for a while ??????? :-).
A huge Thank You to both of you, this information is great and really helps
in figuring out where to go for now. Not sure I have a decision at this
time, but I sure have enough info to speak with the HVAC sub from the
builder, as well as a few others.
This all makes sense, thanks very much for the tips on the High Efficiency
SVL, if I am going to have a gas furnace as backup, and since the "high"
heat only occurs a few weeks a year, what is the advantage then of putting
in a heat pump at all? Is there enough energy savings realized to make the
ROI worthwhile? For me "worthwhile" would be considered 10-15 years, as I
imagine that at about that time I would be looking at potential
repair/replacement of the HP. Given that my "guess", which is very
uneducated at this point in time, of $4000-$5000 for the HP and install this
would mean that I would need to realize a savings of $400-$500 for a
reasonable ROI, ignoring the added cost of yearly servicing.
I am beginning to think that while this technology is interesting, the
cost/benefit to cool the house for a few weeks may not be worth it. Am I
looking at the correct factors here?
Also, if I am looking at a high efficiency gas furnace, specifically a
two-stage, would it be more cost effective to add an AC unit if I decide the
cooling is something that I really "need"?
Thanks, folks, this is really helpful and has yielded, in a short time, a
whole lot more than about 6 hours of Googling....
Yes, this is the proper thinking.
Also a standard air conditioner has fewer parts to cause problems then the
Make sure of one thing that can save you money for installing the air
conditioner later, have them install a coil box on the furnace.
This way the coil can be added easily in the future.
I run heat pumps in the shop and the house, I have 12 tons capacity
total.......the house is 7500sf and the shop is ~ 1600sf
So heres the main thing I know :
When the weather does occasionally dip down to around ~37 degrees here, my
power bills close to abruptly triple because of the electric backup heat
kicking in.......this happens unless I build a nice fire in the woodstove
and / or hack in a water source unit and reject heat from the ground or out
of the swimming pool for a spell..........
Thing about heat pumps for me is that since I basically melt and my body
shifts into low gear when it gets hot, having the ability to also cool is
definately something I need--especially in the shop, as I have machinery in
there that places a large additional cooling load on that system during warm
weather, and most of the year they are relatively inexpensive to operate in
the heating mode in this area.......
So now back to what kj said--if your undecided and under the gun to make a
decision soon, I would agree the best option would be to at least make sure
the ducts are sized sufficiently large and a coil box put in so that ac or
heat pump can be installed at a later date--basically the equipment that
goes inside the house is the same regardless of whether it is a straight A/C
condensor or a heat pump sitting outside on the pad........
Now, I could point you to numerous technical charts and graphs showing
performance curves and that kinda thing about heat pumps, but what you might
find best for finding the least costly system to operate would be to go
ahead and contact your gas company and also the electric company up there
and ask them--usually they have pretty straight forward answers as to the
cost of operation in their area--and they might even have some programs
available where you could get a rebate for installing certain types of
equipment because of energy conservation programs in effect.......
I am the opposite of you when it comes to heat, it doesn't bother me until
it hits 90 with high humidity. In general, ceiling fans do us quite well.
I lived 26 years in Southern California with no AC and it wasn't a problem
Thanks for the info and advice. If memory serves, you are about 2 hours
South of where we live so the climate you are in would be very similar.
Great advice, I will be contacting Puget Sound Energy next week to see what
they have to say. Thanks as well for NOT pointing me to those numerous
charts and graphs. They would just bore and confuse me :-). Now that you
folks have given me the right info to ask the pro's about, I feel much more
comfortable in making an intelligent, well at least semi-intelligent,
Did you say that your temperatures occasionally get to -30F, or 30F? "sub-30"
While I don't get into the numbers much, a heat pump with electric backup
would likely work quite well if you rarely go below 30F. The break-even
point of the pure HP mode can vary quite a bit depending on the unit itself
and specific electrical costs. Installation break-even points can be as
low as the 25F area, and some are in the 35-40F area.
We had a HP/gas combo whose HP unit was quite good to about 25F or so.
That said, even though you may dive below the cutover point, even expensive
heat (electric) _may_ still be optimal if the sub-cutover point temps are
If you say that you almost never get under 30F, then a HP with electric
backup will probably do better than gas, certainly better than pure electric.
Another way of looking at this - a properly adjusted HP unit can _never_
be worse than running on backup heat all the time. So if your backup
heat is electric, a HP/electric combination _cannot_ be worse than pure
Similarly, if your winter temperature are lower, a HP/gas combination
will be significantly better than pure gas, let alone HP/electric (assuming
reasonably standard electric/gas pricing differentials)..
Consider how long your house is above the HP cutover point, but still
needs heat. In your area, as it is in mine, that's a big part of the year.
I suggest consulting a professional HVAC contractor (who doesn't have a
particular axe to grind, or get multiple opinions) and get them to run
the numbers _specific_ for your situation.
In other words, I'm not going to make a specific suggestion other than
asking someone who can run the numbers for you with a knowledge of your
 Where the temperature is low enough for the backup to be more cost-effective
than HP mode. This doesn't factor in backup/long term at all. In other
words, this is approximately the place where the HP _should_ switch over to backup.
Chris Lewis, Una confibula non set est
It's not just anyone who gets a Starship Cruiser class named after them.
I have Carrier heat pump in my sn room. It works quite well for
colling/heating. Even in dead winter with outside temp. ~-30F, it does
the job. Matter is having suffcient capacity to begin with. Under sized
one will never work right. Lucky I have a bro-in-law who is commercial
(stuff snipped for brevity)
It doesn't get below 30 often in this area, we have been here 12 years and I
don't think I have seen it that low for more than a day or two at a time,
and that I've seen only once or twice. It will hover in mid-30's for a week
or so during the winter, but that is not every year either.
And thanks to you folks I now have the knowledge to ask for the right
numbers and to be confident that I can tell if a quality job was done in
gathering those numbers.
Then I take my comment about a HP in your area back, I took it as your low
temp was NEG 30, not 30 degrees F (above 0).
You are in a climate for a HP if your temp seldom goes to 30 above.
Ah, I just looked at this reply closer, what I meant was ~30 (tilde 30)
meaning "about" 30, not minus. No way am I living in a place with -(minus)
30 :-). One of the joys of computers and screen fonts is that some
characters look a bit "iffy" at times, and I had forgotten about that one.
Sorry, folks, for the confusion, my bad.
So, to be sure I understand the technology, the heat pump delivers heating
generally for less cost than even a high efficiency gas furnace, as long as
the temperature is most often above a "floor" which is in the low to mid
30's F above zero. The added bonus is that at the same time cooling is
delivered. The downside is that if the temperatures are often below that
floor, then supplemental heat generation is required. Which method used,
electric/propane/natural gas, can depend upon what sources are available in
a given area and at what price. Have I got this right so far?
The alternative to get both the heating and cooling is to add an AC unit to
an existing furnace. In this case, the cost of fuel on an ongoing basis is
higher than a HP, given that temperatures are generally above the "floor",
but the initial costs may be less. The decision to add AC or an HP could
then be looked at as a simple cost trade-off, as the end result for
heating/cooling would be the same, correct?
And in all cases it is imperative to get the proper sizing information from
a pro in the area and to ensure that the ducting which is place can manage
these types of systems. How am I doing so far?
One thing I have forgotten to ask is about ongoing maintenance. We
generally spend about $125 a year to have a heating company do a yearly
inspection and "tune-up" on our furnace. Are the costs of maintaining an HP
or AC unit comparable, or should I plan for other "normal" maintenance
items? And slightly OT, what about this "duct cleaning" service that is
Thanks again, folks, I think I'm getting there.
HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.