The Manufactured Housing Forums

Depending upon your local rates, but almost always the rule of thumb....Electric heat (strip heat) is the most INEFFIECIENT method for primary heating purposes. Depending upon the square foot of the home in question, requirements could vary from 15kw to more than 30kw nominal heating demands. (Imagine this as having a whole string of those portable, plug in the wall unit heaters that glow orange when on, and cause the wheel on your electric meter to spin like there's no tomorrow). Also note there is a full 100 amp more on the main breaker box, i.e. most doublewides with gas heat come factory with 100 amp main breaker service, while the same home with strip heat have a full 200 amp service. When breaking down the requirements of the home, the majority of that 100 extra amps is dedicated the electric strip heat furnace. Your oven and hot water heater draw no where near what the electric furnace draws. If you question the validity of this info, pop the door off the furnace and look at the size of the breakers on the furnace alone....and note that there is not 1, but 2 of them. Then note the rating on the breakers. Usually 40-50 amp breakers. Keep in mind there are TWO of them. 50 amps times 2 = 100.... If electric is your only option, consider a heat pump, and utilize it as your primary heating (and cooling) source. When the outdoor ambient drops below 32 deg, (give or take a few), then and only then will you utilize your strip heat (2nd stage emergency heat). Electrical requirements on a heat pump in winter months are MUCH less than a furnace with strip heat, as well as drawing less electricity the same system requires in summer months (System pressures due to a high ambient (increased pressures) take more electricity to operate the compressor than the same system with a low outdoor ambient, i.e. hot summer, cool winter). Also keep in mind this is not a big-deal conversion. You'll utilize the same heater, just a few more low voltage wires and installing a heat pump in place of the condensing unit, and a thermostat change. Also note as far as the natural gas to propane conversion, all furnaces manufactured today are capable of this feat, but there is more to it than just the orfices in the burners. You need the change the regulator spring in the gas gas valve as well. You will also need the adjust the valve for the proper fuel flow. (Natural gas: 3.5 inches w/c (water column) versus 10 inches w/c for propane) The home we're looking at has a gas furnace with a 90+% AFUE rating, which is excellent by todays standard (so efficient it condenses and requires it's own drain. Exhaust gas is vented through schedule 40 PVC (you could put your cheek on the flue pipe without any discomfort), and I will STILL utilize a heat pump as my primary heat source. I would not recomend anything less than a 12 S.E.E.R. (Seasonal Energy Efficiency Ratio) heat pump. Bite the bullit and spend the extra bucks in insulation upgrades (at least 19 wall, 22 floor and 30 ceiling). I'll put my manufactured home up against ANY site built home in energy efficiency.....All for about $35.00 - $40.00 per square foot. Hope this helps answer some of your questions...And please keep in mind, Opinions are like *******, everybody has one.

Good luck!

you said..
" as well as drawing less electricity the same system requires in summer months (System pressures due to a high ambient (increased pressures) take more electricity to operate the compressor than the same system with a low outdoor ambient, i.e. hot summer, cool winter). "....

Why would that be???/....The 12 SEER rating you mentioned is the rating of the a/c function...A 12 SEER heat pump and 12 SEER a/c of the same size will all use the exact same power to run on the a/c cycle...

You forget the one most important difference...COMFORT...

If energy efficiency was the only concern that consumers have...we all would be driving tin can small 4 cyl autos...we would never own a pick up or SUV or larger auto...We do because comfort is an important feature of a product..

Heat pumps have much lower duct temperatures than other types of heating systems..causing many folks to feel cold all the time...We get complaints from nearly every customer that has a heat pump for the first time...Often when the ouside temp is around 40..they will start the back up heat system just to feel good and defeat the whole purpose of paying extra for the heat pump..

I had a heat pump in a house I had in Nashville several years ago and I would NEVER have another heat pump. Murray was correct about the comfort factor. In the 40 degree range you get warm not hot air and I would kick on the elements which defeats the concept of a heat pumt. My first choice would be natural gas or propane than electric than wood stove than fire in the middle of the room than heat pump.

BTW: Thanks Murray for the site on the mortgage professor. I ran a refinance proposal through it and cancelled my refinance because it said I would never cover the cost.

Simple Murray, allow me to elaborate. The simplest way to explain in laymen’s terms would be to give you an example. Chlorodiflouromethane (R-22), or our refrigerant for this example has a definitive pressure/temperature relationship that remains constant, dependent upon outdoor ambient (temp). For simplicity sake, let's take a 100 deg. day for our test bed. At 100 deg (on an R-22 scale), we'll be running just under 196 psig (pounds per square inch gauge). This is the true "head pressure" or high side reading of our system. This is the internal pressure that the piston in the compressor must overcome to complete a cycle. Also note that this "compressor" is driven by an electric motor, and as internal pressures increase, so does the amperage required to overcome these pressures resulting in the little wheel on your electric meter to move faster (KPH) or Kilowatt per Hour. The exact amount of electricity (amperage) required can be measured with a simple ammeter connected to the run winding of the compressor. Now we'll take the EXACT system, (our test bed), only this time the outdoor ambient (temp) is now 50 deg. 50 Deg on our R-22 scale is now resulting in a high side (head pressure) of only 84.1 psig. The amperage taken to overcome this internal pressure is substantially less than it is on a 100 deg day, resulting in the little wheel on our electric meter to move much slower, resulting in less KPH usage. This being a given, I do agree gas heat (propane or natural) will burn hotter resulting in an increased output air temp. I will also agree that anyone who has been accustomed to gas heat can tend to be disappointed with a heat pump. A fair example would be 140 deg for gas versus 117 deg. for a heat pump, and can take some getting used to. And while outdoor ambient decreases and approaches the "threshold", efficiency decreases. 35 deg is a good "average", though most manufactures claim efficiency down to 17 deg. My personal opinion is your "peeing in the wind" when ambient reaches 32 deg.or below. A heat pump is more of a "gee, I'm comfortable" temperature, not a "standing over the supply register wet and naked to dry off", no pun intended. In a well insulated home a heat pump can easily maintain an indoor temp of 74 deg, all the way down to a 32 deg outdoor ambient, which is quite comfortable for me. Two years ago we learned a valuable lesson. PSO (our natural gas supplier) got a wild hair up there butt and decided that the cost of natural need to not double, but nearly triple. We were overwhelmed with service calls from people who were certain their gas furnaces were malfunctioning. Upon arriving to their homes, we were greeted with many red-faced people waving their gas bills in front of us, certain that their furnaces were to blame. Unfortunately, the equipment was functioning properly. MANY homes 2000 to 2500 sg. Ft. were receiving gas bills ranging from $500 to $800 for ONE month. Ask anyone who was living in Oklahoma utilizing natural gas as their primary heat source. And yup, the lawsuits began to fly. PSO settled in court and offered it's customers a puny rebate (spread out over the next several years). Big Woo. Alternative fuel sources are indeed worth considering. Also geographical areas are indeed different. Obviously if you lived in Alaska, a heat pump wouldn't be a wise choice. But if you live in a climate where during winter months the temp remains above 32 deg 60%-80% of the time, it's an option worth considering. If your home is "drafty", it's tougher to maintain a reasonable temp regardless of what method you choose. Also worth considering is what it's costing you for each BTU (British thermal unit) regardless of your heat source. If your gas furnace is over 12 years old, your probably achieving a 60% AFUE, meaning 60% of the gas your burning goes into your home as usable heat and 40% goes right up your flu, attempting to heat your yard. Times are changing, and technology is increasing at an alarming pace. Gas furnaces can now achieve an AFUE in excess of 90%, with less the 10% going to waste out your flu. These furnaces are so efficient; they actually "condense" requiring a drain line similar to the one for your air conditioning. So efficient in fact, they have to be vented in PVC pipe due to the acidic mixture created, as it would eat right through galvanized flu pipe that has been utilized for so many years. Variable speed blower motors (DC Inverters) that operate over 12 times more efficient than an AC motor and take less electricity to operate than a 100 watt light bulb. What it really boils down to is personal prefference and just how large a hole in your wallet your willing to live with. When in doubt, RESEARCH.......Learn what is available, and at what initial cost, time to recover from an initial investment, what your investment will save you in energy usage. Hope this clears up any missunderstanding, and as before, this is ONLY my opinion.........Good Luck!

CORRECTION!!!!!!!!

ONG is the natural gas supplier, NOT PSO which is electricity....Sorry for the screw-up.....Irreguardless, BOTH have nearly caused blood vessles in my head to exploid from rate increases.....

1)...Thanks for the info..
2)...Try using paragraphs on long posts...much easier to read and understand..
3)...you said..tech stuff..tech stuff..tech stuff......
BUT..you did not answer the question..Question was...Does 12 SEER a/c use as much energy as 12 SEER heat pump when in a/c cycle...that is...100 degree days each..why would one 12SEER unit be different than the other 12SEER unit..
4)...You mentioned 100 degree day ( on R-22 scale)...from my under standing R-22 is a measurement of insulations effectiveness...What could this possible have to do with the question or temperature out side..?

I went to both the Trane and Carrier sales schools...both make the point the in the a/c function...a straight air and heat pump with the same SEER rating use exactly the same amount of energy..They also correctly point out the heat pumps are much more costly to maintain...Of course this is good for you..

A potential home buyer can save much more money by understnding and shopping finance than anything else..Saving 1/4 % per year will save more money than all the energy saving devices ever built..

The comfort factor cannot be over looked...Consumers what to be able to take a bath or shower without feeling cold..

1. Yes. A 12 SEER heat pump would use the same amount of energy reguardless of whether it was in the heat pump mode or the AC mode on a 100 deg day. (to a degree). Keep in mind when in heat pump mode it's still an air conditioner.....the reversing valve simply reverses the flow of refrigerent....I.E. the indoor evaporator coil becomes the condensor coil (the component that's job is to remove heat), and the outdoor coil (condensor) becomes the evaporator (the component that gets cold due to the refrigerent changing from a high temp gas to a low temp liquid).
2.Your missunderstanding what R-22 is. Has NOTHING to do with "insulations effectiveness. It is simply a "common type" of refrigerent. R-22 is short for dichlorodiflouromethane, or the chemical composition the makes up the refrigerent. (Old cars used R-12, New ones use 134K,.ect)
3. You've missed the boat on the point I've attempted to make. First, it's hard to make an even comparison on energy usage in cooling or heat pump mode on a 100 deg day. We would not even consider utilizing the heat pump mode when the outdoor ambient was 100 deg....unless we wanted to heat things up inside the home...But if it were 50 deg outside , and we were utilizing the heat pump, the the energy required to operate our compressor would be less than it is if the outdoor temp was 100 deg.
4. As far as SEER is concerned, which simply represents the units ability to remove heat more efficiently, whether it's a 10, 12, 14 all the way up to an 18 SEER. A 10 SEER unit (irregaurdless of whether it's a straight condensing unit or a heat pump) cannot remove heat as efficiently as a 14 SEER unit. Why?
a: System Pressures.
b. Coil area.

Take our 100 deg day. But now we have two individual systems, side by side. One is a 10 SEER, one is a 14 SEER. Both are the same tonage. Our 10 SEER unit has a single row condensing coil. Our 14 SEER unit has a double row coil, resulting in TWICE the physical area....which results in the units ability to remove heat more efficiently.
5. Removing more "heat" results in lower pressures.......which results in less amperage taken to overcome these "lower" pressures.....which results in lower electrical usage. Yadda, Yadda, Yadda.
6. I opologize for any missunderstanding. I've attempted to break this down into as much of a "Dr. Suess Fashion" as I can.
7. Pick up a TP Chart.....Any AC Dealer should have one, and probably give it to you a no cost. It will clarify (in easy-to-read chart form) pressure/temp conversion for various types of refrigerents.
8. Heat pumps aren't for everyone. The sad reality is that there are many businesses out there that don't have a clue how to properly charge a heat pump. (Superheat, Subcool, ect.). resulting in poor performance. The system charge on a straight air conditioner is much more forgiving than the charge on a heat pump (especially if attempting to charge it during winter months). If more HVAC contractors were better educated in the theory of heat pumps and how to properly set them up, there would be less complaints from homeowners who are unsatisfied with their systems performance.
9.Anyhow murray, It doesn't sound like a heat pump is for you. To each their own. Stick to your gas or strip heat. It WILL put out warmer air. No doubt about it....But at what cost is the factor that only you can decide.
10. Simple enough. "Nuff said. Good luck and God Bless.

Well, now that I've waded through all that, I think I'll just buy a couple of oscillating fans........................................

LOL!

Better yet would be a large palm leaf and a husband to wave the air at you...

Smile..