Heat pumps?

[Gizzy]

This isn't a garage question as much as a home question.I have a Trane furnace that's starting to show it's age(15yrs.).I know it's only a matter of time before It will need replaced.My question is do any of you guys have a newer heat pump in you home or garage?My son has an older style in his house that he's getting ready to replace,he said the newer ones are more efficient.What do you guys think?Heat pump vs. LP furnace pros & cons.I appreciate any help,Thanks.

 

[dreasoner]

I have a 2 stage gas furnace with a heatpump. I use an outdoor sensor on the stat and switch to gas heat about at about 30 degrees outside. For me it is an ideal setup. I live in Indy.

 

[pseudorealityx]

Any heat pump is far more efficient today than 15 years ago. What's best for you depends on your energy costs, and building infrastructure.

That said, a high efficiency furnace is more efficient than a standard efficiency furnace.

 

[Falcon67]

We put in a new Ruud 14 SEER back in the spring. If it ever gets cold here and we need to call for heat, I'll let you know how it works. So far the AC works well. No $ savings really, but the unit keeps the house cooler by 4-5F for the same money. The old Goodman had three stage strip heat unit that pulled enough amps to slice up a battleship, so when we finally need heat we ought to save big $.

 

[nh_yota]

I do know that some of the newer heat pumps work at colder temperatures so they are becoming more common in colder climates. When heat pumps only worked above 50 degrees or so they were only useful in warmer climates.

 

[theoldwizard1]

This isn't a garage question as much as a home question.I have a Trane furnace that's starting to show it's age(15yrs.).

You should be able to get another 10 or 15 years out that furnace !

Heat pump vs. LP furnace pros & cons.I appreciate any help,Thanks.

My in-laws lived in NW NC and had a heat pump. Their neighbor had a propane forced air furnace and A/C. The in-laws bills were significantly less !

Now, NW OH is not NW NC ! The question is at what outside temperature does
your heat pump start to lose efficiency and when does it stop producing heat all together.

Dreasoner has the perfect solution.

 

[OccupantRJ]

My house has a heat pump and seems to do well. It can get in the low teens here in Eastern NC, and the house is comfortable, so I installed a heat pump in the workshop, particularly because it was a gift.

 

[sms1974]

I'll offer up a little advise, remember it's free so you get what you paid for... I am a Heating contractor, family business 45 years strong in business. We were one of Ohio Edisons top Heat program dealers, we do heat pumps every day of the week...

Today's heat pumps are pretty good, heat pumps 20 years ago were pretty good too, and I've got some Trane units from the late 80's that are still alive and kicking!

A new high efficency heat pump is most likely going to be cheaper than a LP furnace and AC. Insulation is the real key here. Good doors and windows and addiquite insulation will make a bigger difference in your energy bills than choosing between a standard or high efficency unit. Heat pumps are rated two ways, SEER rating this is the 10 / 12 / 14 / 16 # you will hear frequently, This relates more to air conditioning. The more important heating # is the HSPF, these range from 7.5 to 12 on the super high efficency equipment. Obviously the higher the # the better. Another consideration would be a dual fuel system, heat pump and a 95% efficent LP furnace. Up side to that is you don't need neary as big a generator to run a furnace as you do a heat pump. Find a good heating contractor that's willing to look at and listen to your concernes and desires...

 

[theoldwizard1]

Another thought for the OP ...

If a major component in your A/C system "shits the bed", try to find an HVAC contractor that will install a heat pump IN ADDITION to your forced air furnace and wire it like dreasoner's system !! Best of both worlds !!!

 

[nh_yota]

I should also add that a heat pump (in heating mode) is designed to run longer at lower temperature differential than a traditional furnace, i.e. it will run similarly to a modulating gas furnace/boiler with longer run times and lower supply temps.

Using a heat pump for heat can be a big change for people who are accustomed to a furnace kicking on when the thermostat calls for heat, blasting out heat for a few minutes, then shutting off. A heat pump can provide more even heat because of the reduction in the temperature swings and greater circulation (longer blower run times).

 

[bonneyman]

I'm an HVAC contractor in Southern Arizona, and, with our relatively mild winter temps, you'd think HP's would be great. I don't recommend them unless the customer lives in an area where gas service is expensive.

We get alot of older retired folk moving here, and they are just not comfortable with HP heat. (Especially the newcomers who are used to oil or gas heat). "It's not warm enough air!" is a complaint I hear far too often with heat pumps. I can slap in some aux strip heaters - then they gripe about the electric bill.

My advice is: if you have gas available, stick with gas heat.

 

[Dick in Wisconsin]

Does the OP have access to water? Well? Consider a ground water heat pump (GWHP aka geo-thermal) like a WaterFurnace. I have one in a house near Green Bay (WI) which is probably in a colder climate than the OP. It works great summer and winter. Original GWHP was a home made system installed when the house was built in 1955; ran on 480 3 phase. Lasted until 2000. Put in a WaterFurnace to replace it. Well pump still runs on 3 phase.

City has a municipal electric utility, which I "think" offers us lower electricity rates. This helps.

 

[theoldwizard1]

I'm an HVAC contractor in Southern Arizona, and, with our relatively mild winter temps, you'd think HP's would be great. I don't recommend them unless the customer lives in an area where gas service is expensive.

We get alot of older retired folk moving here, and they are just not comfortable with HP heat. (Especially the newcomers who are used to oil or gas heat). "It's not warm enough air!" is a complaint I hear far too often with heat pumps. I can slap in some aux strip heaters - then they gripe about the electric bill.

My advice is: if you have gas available, stick with gas heat.

Gas is VERY cost effective especially when the temp gets below freezing.

 

[theoldwizard1]

Does the OP have access to water? Well? Consider a ground water heat pump (GWHP aka geo-thermal) like a WaterFurnace.

I am a big fan of GWHP, but not WaterFurnace. IMHO, they train their installers to have insufficiently sized heat transfer loops.

IMHO, any GWHP system should have a ground loop(s) capable of supplying 50-60F water 12 months of the year. NO EXCUSES.

I have read too many posts, here and elsewhere, about unhappy GWHP owner with high heating bills caused by the use of electric resistance heat because the inlet water is below 40F !! Simply undersized.

 

[DC73]

I have a 2 stage gas furnace with a heatpump. I use an outdoor sensor on the stat and switch to gas heat about at about 30 degrees outside. For me it is an ideal setup. I live in Indy.

I like this dual fuel approach and it works very well especially where gas costs are reasonable.

The problem with heat pumps alone is that they do not produce a "hot" air from the vents like a furnace. The air temp from the vents is more moderate and I don't care for it personally. A bit too chilly for my skinny bones.

The dual fuel setup like dreasoner has is great because you can set the gas to come on at an outdoor temperature you specify and get the warmer air you desire when it's most needed. If you can get your head around electric vs gas costs and can monitor them, you can adjust the changeover setting as needed to provide the best bang for the buck. If electricity proves cheaper, set the switch point for a lower temperature. If gas proves cheaper, set the switch point higher.

DC

 

[sms1974]

I am a big fan of GWHP, but not WaterFurnace. IMHO, they train their installers to have insufficiently sized heat transfer loops.

IMHO, any GWHP system should have a ground loop(s) capable of supplying 50-60F water 12 months of the year. NO EXCUSES.

I have read too many posts, here and elsewhere, about unhappy GWHP owner with high heating bills caused by the use of electric resistance heat because the inlet water is below 40F !! Simply undersized.

I think this conversation / argument has been had before...

when planning a loop you have to take in to consideration several factors. Yes a consistent 55 degree temperature would be fantastic, and yes it is possible but at what cost? It's not so much the cost of loop materials or the cost to install it but the cost to pump the fluid through it. In some areas to be able to insure a 55 degree loop at any temperature you would have several thousand feet of pipe. You have to have a pump capable of moving the fluid through all that pipe, some times 2 or 3 pumps. All those pumps eat up electricity. Long story short all your savings in having a 55 degree water temp are burned up in the electric used by the pumps...

And yes I have several systems designed and installed that will have 30-35 degree loops in January and February that continue to provide adequate heat at a very reasonable cost.

 

[theoldwizard1]

when planning a loop you have to take in to consideration several factors. Yes a consistent 55 degree temperature would be fantastic, and yes it is possible but at what cost? It's not so much the cost of loop materials or the cost to install it but the cost to pump the fluid through it. In some areas to be able to insure a 55 degree loop at any temperature you would have several thousand feet of pipe. You have to have a pump capable of moving the fluid through all that pipe, some times 2 or 3 pumps. All those pumps eat up electricity. Long story short all your savings in having a 55 degree water temp are burned up in the electric used by the pumps...

First, I have no formal training or first hand knowledge of GWHP systems.

But I have done a lot of research and have found that the people complaining about poor heating performance have inlet water temperatures below 35F. Because of other design issues, the only way to get adequate heat is through electric resistance heat, which is very expensive to operate.


IMHO, if the installer can can guarantee an inlet water temp above 50F, 12 months of the year, then that area is not well suited for a loop based GWHP. Well(s) might be more cost effective. In either case, the customer needs to be informed that a GWHO syste is NOT a good fit for them !

 

[sms1974]

First, I have no formal training or first hand knowledge of GWHP systems.

But I have done a lot of research and have found that the people complaining about poor heating performance have inlet water temperatures below 35F. Because of other design issues, the only way to get adequate heat is through electric resistance heat, which is very expensive to operate.


IMHO, if the installer can can guarantee an inlet water temp above 50F, 12 months of the year, then that area is not well suited for a loop based GWHP. Well(s) might be more cost effective. In either case, the customer needs to be informed that a GWHO syste is NOT a good fit for them !

Todays systems are much better engineered and designed than those that were done 30 years ago. A properly designed and implemented Geothermal heat pump is very energy efficient and very capable of maintaining house temperatures without supplementary heat via resistance strip heaters.

Of course I also have seen very poorly designed or badly installed systems that do not provide adequate heat for the homes there installed in. The down side is of course the upfront cost and with the uncertainty of the cost of electricity today and in the future the payback period becomes longer and longer... The only thing driving Geothermal sales today is the 30% tax credit, if they allow that to expire at the end of 2016 as it is scheduled to it will be the death nail for geothermal...

 

[pseudorealityx]

I think this conversation / argument has been had before...

when planning a loop you have to take in to consideration several factors. Yes a consistent 55 degree temperature would be fantastic, and yes it is possible but at what cost? It's not so much the cost of loop materials or the cost to install it but the cost to pump the fluid through it. In some areas to be able to insure a 55 degree loop at any temperature you would have several thousand feet of pipe. You have to have a pump capable of moving the fluid through all that pipe, some times 2 or 3 pumps. All those pumps eat up electricity. Long story short all your savings in having a 55 degree water temp are burned up in the electric used by the pumps...

And yes I have several systems designed and installed that will have 30-35 degree loops in January and February that continue to provide adequate heat at a very reasonable cost.

That's ridiculous. The pumping energy 'lost' by having long loops is offset almost immediately by the cost difference between being able to run a refrigerant cycle based heat pump vs. using strip heat. It's not even close.

Yes, you need large loops. That's the whole point of being able to take advantage of GW. If you want some system that will work for 'part' of the winter, just use air side heat pumps and save all the first cost. If you're going to do ground loop, size it so it ALWAYS works.

 

[Ohmthis]

i also have a duel fuel (heat pump with lp furnace for back up) system. My heat pump puts out 97* heat at 25 outside.i have my change over set at 20*. I installed (over a decade in the hvac industry) it a little under 4 years ago. I've always advised if you have NG available, then go with a high efficency furnace and straight AC. If you don't, and do not live in a VERY cold climate, then heat pump with (I prefer LP) suitable back up. Good luck! My highest electric bill for winter is $187. Most around here were in the $500-$600 range for the same month.

 

[shillamus]

I have ductless splits with baseboard backup in my home

check out blueridge ductless splits

http://www.alpinehomeair.com/viewpr...d_yQcvMfWAqW5HdwbZ7oUi69tqBVTFNe28aArAq8P8HAQ

ductless splits let you zone your energy usage

I am not happy with baseboard backup heat but it works.. It would be nice to have a pellet stove

 

[Jackfre]

I have done a lot of second stage heat with the Rinnai Energysavers. Totally separate from the duct system, which keeps things simple, which is good

 

[sms1974]

That's ridiculous. The pumping energy 'lost' by having long loops is offset almost immediately by the cost difference between being able to run a refrigerant cycle based heat pump vs. using strip heat. It's not even close.

Yes, you need large loops. That's the whole point of being able to take advantage of GW. If you want some system that will work for 'part' of the winter, just use air side heat pumps and save all the first cost. If you're going to do ground loop, size it so it ALWAYS works.

I think your getting lost in translation...

There are several different loop styles but basically two different loop types. You either have a ground coupled system where your pumping ground water to the unit and then discharging it at a location away from where it came from. And or a sealed loop. If you have ground water that is of addiquite quality and quantity that's your best choice. Unfortunately it's very uncommon. Most of the time you are going to have a sealed loop, either a bore hole (aka well) horizontal loop or a pond loop. In northern Ohio on average if your doing a bore you will end up with 135-175 foot deep bore per ton of heat pump. Horizontal loops can easily be 300-600 foot again per ton. Pond loops are the shortest at an average of 100 foot per ton. So we have to have enough pump to push the fluid ( water ) through all this pipe. To push enough fluid at the proper flow rate to create a turbulent flow. These pumps can use quite a bit of electricity to do this. If you design your loop to consistently give you 50+ degree fluid you will end up with loops possible double or triple the length, which will require even more pumping power...

Yes 50+ degree fluid will give you more BTU (Heat) than 30 degree fluid. But how much and what will it cost to run the pumps required to acheve this...

As far as a system that will heat your home without strip heat. I have several dozen rural homesteads with heat strips that have never been on. The biggest improvement in the geothermal heat pump has been dual stage equipment. A dual stage unit my be sized large enough to deliver enoug heat on the coldest day with a 30 degree fluid temp yet not be to big on a 50 degree day with a 50 degree fluid temp...

 

[Falcon67]

But I have done a lot of research and have found that the people complaining about poor heating performance have inlet water temperatures below 35F. Because of other design issues, the only way to get adequate heat is through electric resistance heat, which is very expensive to operate.

"Expense" is proportional IMHO. I looked at the backup resistance element in our new heat pump system and it's no way in hell comparable to the 12.5kW worth of elements in the old system. It's more like whats in the 5K I use in the shop. Comparing the two here, if we have to run with resistance a while, it's BFD.

Our contractor said the number 1 complaint he has on a heat pump retrofit - including his wife - is that "the system blows cold air!" "Cold" being air in the mid 80~90F range. My wife HATES dry heat and when she heard that, she was like "awesome".

 

[pseudorealityx]

I think your getting lost in translation...

There are several different loop styles but basically two different loop types. You either have a ground coupled system where your pumping ground water to the unit and then discharging it at a location away from where it came from. And or a sealed loop. If you have ground water that is of addiquite quality and quantity that's your best choice. Unfortunately it's very uncommon. Most of the time you are going to have a sealed loop, either a bore hole (aka well) horizontal loop or a pond loop. In northern Ohio on average if your doing a bore you will end up with 135-175 foot deep bore per ton of heat pump. Horizontal loops can easily be 300-600 foot again per ton. Pond loops are the shortest at an average of 100 foot per ton. So we have to have enough pump to push the fluid ( water ) through all this pipe. To push enough fluid at the proper flow rate to create a turbulent flow. These pumps can use quite a bit of electricity to do this. If you design your loop to consistently give you 50+ degree fluid you will end up with loops possible double or triple the length, which will require even more pumping power...

Yes 50+ degree fluid will give you more BTU (Heat) than 30 degree fluid. But how much and what will it cost to run the pumps required to acheve this...

As far as a system that will heat your home without strip heat. I have several dozen rural homesteads with heat strips that have never been on. The biggest improvement in the geothermal heat pump has been dual stage equipment. A dual stage unit my be sized large enough to deliver enoug heat on the coldest day with a 30 degree fluid temp yet not be to big on a 50 degree day with a 50 degree fluid temp...

You don't need to lengthen the bores to keep a more consistent temp. You just add MORE loops/bores. Pumping costs remain mostly unchanged. Pumping losses are calculated by the longest run... NOT the total length of all loops.

 

[sms1974]

You don't need to lengthen the bores to keep a more consistent temp. You just add MORE loops/bores. Pumping costs remain mostly unchanged. Pumping losses are calculated by the longest run... NOT the total length of all loops.

You are correct that you don't have to go deeper you can add additional bores or additional circuits on a horizontal loop... You still have pump water through all of it... However all of your circuts have to be the same length, water takes the path of least resistance if you have one loop that is short it will effect how the flow is through all of the circuts. You can have 10 circuts if you want but they all must have the same length. Also you have to have enough pump to push all the fluid. A loop with 4 circuts will take less pump than a loop with 8 circuts...

We are so far off what the original thread was about here which is not my intention.

If someone would like to continue this discussion is be happy to but in another thread...

 

[Jackfre]

You are correct that you don't have to go deeper you can add additional bores or additional circuits on a horizontal loop... You still have pump water through all of it... However all of your circuts have to be the same length, water takes the path of least resistance if you have one loop that is short it will effect how the flow is through all of the circuts. You can have 10 circuts if you want but they all must have the same length. Also you have to have enough pump to push all the fluid. A loop with 4 circuts will take less pump than a loop with 8 circuts...

We are so far off what the original thread was about here which is not my intention.

If someone would like to continue this discussion is be happy to but in another thread...

...and if you have those loops of equal lengths you must understand "reverse return". Essentially you are equaling the pressure drop in each leg. Essentially the rule of thumb is "first on, last off"

 

[sms1974]

...and if you have those loops of equal lengths you must understand "reverse return". Essentially you are equaling the pressure drop in each leg. Essentially the rule of thumb is "first on, last off"

Absolutely correct...