Differences between a/c and heat pump??

[Bill Stockard]

[Hey Bill, Im surprised your unit can make heat down to those cold of temps with no assist from the auxillary, that makes my above post inaccurate. Sounds like theyve come a long way in technology since I purchased mine 7 or 8 years ago. We bought a Carrier which was one of the better models you could get at the time

Yeah, I didn't believe the HVAC contractor before our heat pump was installed, but it has worked beyond my expectations. This is what I have without the solar option: http://www.lennox.com/products/heat-pumps/XP21/

For years I had heard about heat pumps blowing cool air and taking forever when the temperature was in the low 20s and below and it was why we never owned a heat pump previously, but have been pleasantly surprised. All of our previous homes were all electric and heated with an electric furnace which were effective at any temperature, very reliable, but expensive to run.



Bill

 

[RVTRKN]

JJpage, the Scroll's are more efficient and have proven themselves over the last 10 years, now that they have been mostly used with small AC systems, but rethink your refrigerant choice. R22 will be so expensive in a couple of years, and I'm already hearing customers groan when I tell tell that the 3 pounds of refrigerant I just charged in their system cost them $100. 00, and thats just for the refrigerant. Most systems take 5-8 lbs on average for a residential system, If it leaked out then the cost of repair will follow the ref. charge the next cooling season and cost more money.



R410a does work, if the system was engineered and designed properly for the new refrigerant, in other words stay with the top brands. Also make sure the evaporator and the condenser are matched for each other, in other words don't buy different brand components. They have been tested and proved to work with the brand you have chosen, but when you mix components, thats when they start to have issues. Also don't reuse the refrigeration lines, the different oils can get mixed and they are not compatible, and don't fall for the "flushing the Line Set technique", (refrigerant lines) its too risky.

 

[HBarlow]

Our house in Lubbock, built in 1992, has a heat pump and a back-up natural gas furnace. The heat pump is apparently controlled by limit switches that shut the heat pump off and shift heating to the gas furnace below 40°. I've never been very impressed with it.

I'm sure newer heat pump systems are more efficient and much improved now but I would not want one in an RV. I haven't studied them but would guess that an RV heat pump costs a lot more than a standard roof ac unit and ordinary propane gas furnace and probably has a shorter service life.

 

[RVTRKN]

Bill, the strip heat systems are expensive to operate and the new Heat Pumps make more since in today's world, but if propane or natural gas is available, then HP's are not advised.

 

[mwilson]

Bill, the strip heat systems are expensive to operate and the new Heat Pumps make more since in today's world, but if propane or natural gas is available, then HP's are not advised.

I am convinced when the wife and I buy our last home before retirement that it will be heated with propane, it is way cheaper than heating with K-1 or #2 fuel oil nowadays. Plus the quality of the fuel oil has really gone downhill in the last several years.

I find the heat pump discussion on here fascinating and may see if a heat pump would be worth adding using a propane furnace to take over at temps below 30 degrees.

A/C in vehicles and houses was a rare luxury up here 30 years ago, now very common.



Mike.

 

[RVTRKN]

Back to RV's, a heat pump in a RV if designed properly are OK, but the gas furnace does more than heat the space, it also heat's the tanks. If the HP is ducted around the tanks, Ok then. As far as efficiency is concerned, mostly the parks include the electricity, so you don't see the cost. I have installed strip heat in my roof AC before, but never used it, I thought that with the new AC I just installed, the cost of adding the strip heat was minimal.

 

[RVTRKN]

Mike, the HP/Gas system combo's, are not advised in mild climate, mostly in the Southern States, but if Gas/Propane is available then buy a larger system to compensate and get it in a two stage system, that way the furnace will be more efficient in mild temps. I can't tell you how much money has been made from the "EMERGENCY HEAT MODE" selection on the thermostat, that locks out the compressor operation when selected. A lot of people think "emergency heat" means, that if its really cold, then it is an emergency and will heat up faster if you chose that mode, but if no other heat capability is present (electric or gas) in the system, then it will just blow cold air. The combo HP/Gas furnace doesn't make since to me, if it turns off the HP under a specific ambient temperature. If gas/propane is cheaper then why use the HP in mild temps? You could install a HP and not use the heat mode that way you'll have it to help in critical situations, but if the condenser is air cooled then its worthless. Now if you have a deep pond that doesn't freeze over completely, then a water cooled condenser will allow all temperature use.

 

[JR]

At our last home our primary heat was heating oil. When fuel prices jumped through the roof and broke the $4. 00 per gallon mark for the first time we were literally looking at tripling our heating bill. Thankfully that first winter I fell into a smoking deal on 400 gallons of fuel, it was left over at a job and the general contractor who was from California could not take it with them and literally gave it away to avoid paying to dispose of it. That bought us a lot of time to sit back and figure out the best course of action. In that time propane began trickling up and even coal and wood pellets began climbing in price, probably due to demand. I have a friend in the hvac buisiness and he turned us on to the heat pump. It dropped our heating oil usage drastically. Yes it did up our electric usage but the trade off was well worth it. We have 2 full seasons of cool weather and even at times in the winter time it may get up to 30 degrees so the heat pump ran probably 70 percent of the time compared to the oil furnace. The only time the furnace would kick on was when the heat pump went into defrost or when it dropped below 25*. As far as the heat strips my friend suggested we stay away from them as they really spin the meter when they kick on, not the most effiecient route. Of course this was just one persons opinion and it was several years ago. The set up worked well for us, and I would like to add one to our current home.

 

[HBarlow]

I am convinced when the wife and I buy our last home before retirement that it will be heated with propane, it is way cheaper than heating with K-1 or #2 fuel oil nowadays. Plus the quality of the fuel oil has really gone downhill in the last several years.
I find the heat pump discussion on here fascinating and may see if a heat pump would be worth adding using a propane furnace to take over at temps below 30 degrees.
A/C in vehicles and houses was a rare luxury up here 30 years ago, now very common. Mike.

Mike,

I recommend you investigate the systems and fuel available and carefully compare prices and average annual heating costs before you buy or build a home with propane heat. My farmhouse is heated with a new brand name propane furnace. Natural gas is not available out here in rural areas so my choices were all electric or propane. The system keeps the house warm and comfortable but it consumes expensive propane at an obscene rate.

It's a 70 year old house with no insulation in the wall cavities but I did have thick insulation blown in the attic and all new insulated windows and doors installed. After paying the propane bills this winter I'm looking for a contractor to bore holes at the top of each stud cavity on the inside of all exterior walls and blow insulation in. The house is brick so access must be from the inside walls.

I had insulation blown in the stud cavities of a house in San Diego in the '80s that resulted in a huge improvement in comfort in that house.

 

[mwilson]

Mike,



I recommend you investigate the systems and fuel available and carefully compare prices and average annual heating costs before you buy or build a home with propane heat. My farmhouse is heated with a new brand name propane furnace. Natural gas is not available out here in rural areas so my choices were all electric or propane. The system keeps the house warm and comfortable but it consumes expensive propane at an obscene rate.



It's a 70 year old house with no insulation in the wall cavities but I did have thick insulation blown in the attic and all new insulated windows and doors installed. After paying the propane bills this winter I'm looking for a contractor to bore holes at the top of each stud cavity on the inside of all exterior walls and blow insulation in. The house is brick so access must be from the inside walls.



I had insulation blown in the stud cavities of a house in San Diego in the '80s that resulted in a huge improvement in comfort in that house.

I know that is a little off topic regarding the OP's question but I am sure that some of you are considering the same things facing retirement as the wife and I are.



We are strongly considering a new modular or double wide as finding a decent contractor up here lately to stick build a home is a huge undertaking. The quality of construction and high insulation R values make the newest manufactured housing an attractive choice. As tight as they are built the heat pump concept could save me some serious money for energy.

It may not increase in value as our last several homes have done but it will be the last one so our viewpoint is different now. When we are gone it will be the kids problem... .....



We are looking at land one town over as the property taxes over there will be a 1/4 of what they are here. That alone will make a huge difference in our cost of living. Will also be designed to drain quickly so that I can shut it down for the winter and hook onto the fiver for points south or west.



We have also considered building a huge garage and installing a cement pad with hook ups to park a four season fiver on rather than having a conventional home for the summer. Water and other utilities could be located in the garage and again be easily drained and secured before heading out for the winter.



It is an ongoing discussion as we both know that we need to change our thinking. Between the property taxes, the heat, extra maintainence from facing the water and two flights of stairs our present digs will not be a good home to retire in.



Have to build an MDT or Class 8 to pull a bigger fiver with if we go that route..... :-laf



I know how to feed and care for one of those bad boys.



Mike.

 

[BIGNASTY]

I know that is a little off topic regarding the OP's question but I am sure that some of you are considering the same things facing retirement as the wife and I are.



We are strongly considering a new modular or double wide as finding a decent contractor up here lately to stick build a home is a huge undertaking. The quality of construction and high insulation R values make the newest manufactured housing an attractive choice. As tight as they are built the heat pump concept could save me some serious money for energy.

It may not increase in value as our last several homes have done but it will be the last one so our viewpoint is different now. When we are gone it will be the kids problem... .....



We are looking at land one town over as the property taxes over there will be a 1/4 of what they are here. That alone will make a huge difference in our cost of living. Will also be designed to drain quickly so that I can shut it down for the winter and hook onto the fiver for points south or west.



We have also considered building a huge garage and installing a cement pad with hook ups to park a four season fiver on rather than having a conventional home for the summer. Water and other utilities could be located in the garage and again be easily drained and secured before heading out for the winter.



It is an ongoing discussion as we both know that we need to change our thinking. Between the property taxes, the heat, extra maintainence from facing the water and two flights of stairs our present digs will not be a good home to retire in.



Have to build an MDT or Class 8 to pull a bigger fiver with if we go that route..... :-laf



I know how to feed and care for one of those bad boys.



Mike.

Mike

If you are going to build your own place might I suggest looking into these two products. They are how we built ours,SIL and BIL's and as soon as snow clears the ground our Sons new place. They are fast BUILD and SUPER EFFECIANT. We have 3 wood stoves and the wood kitchen stove and its 3 to many stoves for the house. It can be cold as the North Pole outside and we have to crack a window cause its hot as hell in the house with 1 stove cooking for heat. The thing that we liked about the build is that the home shell can be built and the inside walls are ALL non load bearing walls, meening you can make room and size of rooms as you wish. The cost is comparitive to conventional stick built homes, but when the family built ours they had a weather tight shell done if a week. The foundation was already in as was the septic system and the well had been in for a couple of years. The ICF foundation works great didnt have to dig as deep for the foundation (below frost line) so instead of 4ft foundation we only had 2ft deep and being all monolithic slab/foundation that is insulated makes the lower part of the house nice to be in.



http://www.sipbuilthomes.com/index.php



http://www.smartblock.com/

 

[JJPage]

JJpage, the Scroll's are more efficient and have proven themselves over the last 10 years, now that they have been mostly used with small AC systems, but rethink your refrigerant choice. R22 will be so expensive in a couple of years, and I'm already hearing customers groan when I tell tell that the 3 pounds of refrigerant I just charged in their system cost them $100. 00, and thats just for the refrigerant. Most systems take 5-8 lbs on average for a residential system, If it leaked out then the cost of repair will follow the ref. charge the next cooling season and cost more money.

I have a stash of both R-12 and R-22 .

If you have a leaky system, and a tech just keeps re-charging, better hire someone new. Any leak more than a deminimus amount, is required to be logged and repaired. While in the HVAC industry, my exposure mostly consisted of commercial rooftop package units, centrifugal chillers w/cooling towers, and large split systems. Residential and auto/rv applications, while I clearly understand their operation, are not my strong suit.

I totally agree with you about not mixing and trying to match components of different capacities, with all the different metering devices, coil ratings, electronic incompatibilities etc, you are really borrowing trouble.

Jess

 

[RVTRKN]

Unless they have changed the law, I can charge a one time unlimited amount for a small system, if more than 20% leaks out over the year, I have to repair the leak before recharging. The customer can always call another company to charge it if they want to. FWIW, I always recommend repairing the leak for residential and commercial units, in fact, I just charged a unit yesterday that the owner would not authorize repairing the leak and asked me to just charge it, which I did. Customers don't always have deep pockets, especially with the many commercial buildings vacant that they own. Owners of strip malls with 50% vacancy just want to get through the emergency and hope its a small leak, and if tenant doesn't complain will leave it that way.



Citizens are going to have a wake up call in the next few years, when it could cost more than the unit is worth, when their unit loses its refrigerant.

 

[Bill Stockard]

Bill, the strip heat systems are expensive to operate and the new Heat Pumps make more since in today's world, but if propane or natural gas is available, then HP's are not advised.

At the last three homes we have built, natural gas was too far away to be practical and didn't want propane in our house. We've always built/owned all electric houses and they were easily and quickly sold when we decided to sell them.



Bill

 

[RVTRKN]

Thats the way it is in some communities. Propane is subject to Oil prices and can vary. I just installed a Rheem package unit on my Dads rooftop replacing the old one, and he has propane and tries to save money by burning wood in his wood stove sitting in the living room. Depending on the part of the US you live, can be cheaper with all electric homes.

 

[Wingate]

I know that is a little off topic regarding the OP's question but I am sure that some of you are considering the same things facing retirement as the wife and I are.



We are strongly considering a new modular or double wide as finding a decent contractor up here lately to stick build a home is a huge undertaking. The quality of construction and high insulation R values make the newest manufactured housing an attractive choice. As tight as they are built the heat pump concept could save me some serious money for energy.



Mike.

Mike, It DOES save unbelievable amounts of $$$$ to install a heat pump system in a double wide. Although this thread has taken a turn from RVs to HP in general, I have found it to be very interesting reading...

My brother is an a/c guy that has owned his own business for about 15 years. Back in 2007, I got sick of the wimpy 4 ton conventional 22 system in our doublewide. During the hot Texas summers, it struggled to maintain 75-77 degrees in the daytime, not to mention the electricity bills knocking on the $400. 00 mark. I sent the dogs and the wife to a relatives house one Friday evening, and we gutted the entire HVAC system in my home. Replaced it with a 5 ton 410 HP, included fully integrated digital thermostat, wireless touchscreen remote, etc... and had the system back up and running by breakfast time Saturday morning. In the record setting summers we have had since, our air system breezes by on a 103 degree day, easily maintaining whatever temp we choose to program it for. Since installing that system, we have yet to receive over a $150. 00 electric bill summer or winter. I believe some of the older HP controls has to be manually switched from HP to Em heat, the newer programmable controls allow you to set what temp youu want it to shift to Em heat. .

 

[JJPage]

Unless they have changed the law, I can charge a one time unlimited amount for a small system, if more than 20% leaks out over the year, I have to repair the leak before recharging. The customer can always call another company to charge it if they want to. FWIW, I always recommend repairing the leak for residential and commercial units, in fact, I just charged a unit yesterday that the owner would not authorize repairing the leak and asked me to just charge it, which I did. Customers don't always have deep pockets, especially with the many commercial buildings vacant that they own. Owners of strip malls with 50% vacancy just want to get through the emergency and hope its a small leak, and if tenant doesn't complain will leave it that way.

Citizens are going to have a wake up call in the next few years, when it could cost more than the unit is worth, when their unit loses its refrigerant.

I can't imagine any of the epa laws being less stringent today than they were when I changed profession. If a leak were actually visible (or not, which many are not), it had to be repaired before the system could be recharged, regardless of what the owner requests.

Your 1st sentence in the above post contains language/verbiage that is suspect to say the least, what constitutes a "small" system?, how do you determine if more or less than 20% of the total charge has leaked? On the second question, you would have had to known the weight of the original charge which is sometimes listed, or you would have had to weighed it in yourself after a repair and then documented it, now a year later if low on charge, you would once again have to evacuate and weigh the charge to determine a >< 20% loss. In real world situations, I know this does not take place, and epa regulations are not that lax.

Like I stated above, my experience was with commercial applications for a major telecommunications giant, we were subject to audits by our own environmental/safety personal as well as the epa on an annual basis. Your situation may be under less scrutiny than I was placed in, good for you, I hate the epa for the most part, but they are able to ruin your day if they deem you careless/reckless... .

I still vote no, on the heatpump from Dometic (other), in an RV application. Jess

 

[RVTRKN]

OK, now I'm going to have to look up regs. That is what I remember from 1997, when I took and was issued my Universal refrigerant lic. Thanks for the heads up.

One negative issue with the RV heat pump, besides not heating your tanks, is when your dry camping, there will be no need of a generator if in cold temps.

 

[RVTRKN]

JJPage, I think you opened a can of worms for me, open the link and give me an opinion, I don't want to tell customers any untruths, notice I didn't say lies. look up "Repairing Leaks" the literature has a copy write of 2005.

https://www.dropbox.com/s/besjadk3u8m6quh/HART 1407 system evacuation #5.ppt

 

[HBarlow]

I know that is a little off topic regarding the OP's question but I am sure that some of you are considering the same things facing retirement as the wife and I are.

We have also considered building a huge garage and installing a cement pad with hook ups to park a four season fiver on rather than having a conventional home for the summer. Water and other utilities could be located in the garage and again be easily drained and secured before heading out for the winter.

It is an ongoing discussion as we both know that we need to change our thinking. Between the property taxes, the heat, extra maintainence from facing the water and two flights of stairs our present digs will not be a good home to retire in.

Have to build an MDT or Class 8 to pull a bigger fiver with if we go that route..... :-laf

I know how to feed and care for one of those bad boys.

Mike.

I think building a large insulated steel building with an apartment inside and room for parking a fifthwheel, car, truck, tools, lawn equipment, etc. is an excellent, practical, and affordable idea.

My wife and I had been looking for a five to ten acre rural parcel we could buy for several years and were considering erecting a building like that when I found this wonderful old brick farmhouse on five rural acres. I paid about half the price of a new steel building for the house and five acres and the house is in excellent shape! I had enough money left to put up a 43' by 60' building and put all my toys in it but I would have been perfectly happy to build the building and and apartment inside. I've seen and admired lots of them around the country. They are perfect for snowbird RVers who want to live in cold country during summers and escape south in winter. When closed up for the winter they look like a storage building.

New steel building construction costs a fraction of the per square foot price of a new stick built home and requires less maintenance.