Heat Pumps versus Central Air Conditioners In this age of high energy costs and environmental awareness, choosing the right cooling system for our homes is a crucial decision. The two main options are air conditioning systemsLet's take a look at how they compare. Heat pumps actually operate as both heating and cooling systems. In the cooling mode, they take heat from the internal air of the home and pump it to the outdoors. To produce heat, they collect it from air, water, or the ground outside and move it inside. Here's a simple way to describe what these units do: they move heat from one place to another. Both heat pumps in cooling mode and air conditioners use the Seasonal Energy Efficiency Rating (SEER), which tells how efficiently they use electricity. The higher the rating, the less power they consume. Heat pumps must now have a SEER of at least 13. A higher SEER is desirable in a warm climate because of the need to more frequently provide cool air to the home.

also are rated according to the Heating Seasonal Performance Factor (HSPF), which refers to the power used when the unit is in heating mode. pump's coils are outside, they become ice collectors during the winter. Heat pumps use burners to melt the ice and push warm air into the house. In colder climates, this increases the operating costs. Air conditioners manufacture cool air by evaporating Freon or some other refrigerant product. Basically there are coils both inside (for cold air) and outside (for warm air). a compressor to change Freon into hot, high-pressure gas that travels through the coils. so, it loses its heat and becomes liquid; the liquid in turn goes through a valve and evaporates intoWhen it enters the coils, it absorbs the indoor heat and lowers the temperature. Residential air conditioners also use the SEER as a measure of their efficiency. often measure energy efficiency by the Energy Efficiency Ratio (EER). This measure shows the number of British Thermal Units (BTU) of

cold air provided for each watt of electricity. When talking about cooling units, 1 ton is equal to 12,000To find the EER of an air conditioner, divide the BTU rating by the wattage. For example, let's say that a 12,000 BTU air conditioner uses 1600 watts to run -- then its EER (12,000 divided by 1600) is 7.5. The higher the EER, the more efficient the air conditioner, so a higher EER is more desirable. drawback is that more efficient units are more expensive.thermostat for ac unit Up to 20.00 SEER/10.00 HSPFoutside ac unit running winter Quietest sound rating of 54 dB at       minimum speedroof ac/heating unit Next level humidity control Up to 18 SEER/10 HSPF Up to 18.00 SEER, 9.50 HSPF Up to 17.00 SEER, 9.60 HSPF

Up to 17.25 SEER, 9.6 HSPF Up to 16.00 SEER, 9.50 HSPF Up to 14.00 SEER, 8.20 HSPFThe outdoor unit of a Fujitsu ductless minisplit system. With the exception of one week in February 2011 where I switched back to the oil boiler to take some data before it went away, the Fujitsu 12RLS has now been heating the house for two years. The dedicated meter for the heat-pump system reads 2,584 kWh. So, it cost about $250 per year to heat our house, in mostly milder-than-normal weather. This is about 1/4 the cost of operating the oil heating system. Most houses in the Northeast have a boiler and forced hot water heating, and most of the rest have a forced-air furnace; both are central heat systems. Without some energy retrofit work, most houses can't be converted over to a single-zone minisplit and have adequate heat throughout the house. In cases where the central heating system is due for replacement, a multizone minisplit may be worth considering. We've done just that at South Mountain Company for a client with a 30-year-old boiler and a poorly designed distribution system.

That system cost over $20,000 installed, though. GBA Encyclopedia: Ductless Minisplit Heat Pumps Will Minisplits Replace Forced-Air Heating and Cooling Systems? Heating a Tight, Well-Insulated House New Englanders Love Heat Pumps Heat-Pump Water Heaters in Cold Climates Air-Source or Ground-Source Heat Pump? Are Seven Heads Better Than Three? BLOGS BY MARC ROSENBAUM Ductless Minisplit Performance During Cold Weather A Tough Energy Code Is the Worker’s Friend Installing a Photovoltaic System Living With Point-Source Heat Seasonal Changes in Electrical Loads A single-zone minisplit costs about $4,000 installed. In cases where the entire house doesn't need to be fully heated, or houses in which a point-source heater can carry the load of the house in mild winter weather, a minisplit can be a great retrofit. In the Pacific Northwest, a major study has been conducted using a single-zone minisplit as a retrofit to the many electrically homes there.

On average they have shown a 40% reduction in heating energy, with some homeowners experiencing much higher savings (the ones most likely that kept the doors to the bedrooms open!) In the studied homes, the electric-resistance heating units were left in place, to be used as needed. It's very possible to consider a similar approach in fossil-fuel-heated homes. The best candidates are houses with open plans, so the heat pump can heat a good portion of the kitchen/dining/living space, and houses where the other rooms are located where natural convection (warm air rising) can transport heat to them. It would be best for the existing heating system to be one that has more than one zone, so that the zone(s) not well heated by the heat pump can still be heated by the existing system. Best suited might be houses where a number of the rooms are not occupied: for example, a large house with a single occupant who needs a bedroom, bath, and the public areas heated, but not the other four bedrooms and two baths.

In essence, it's going back to the days when a central hearth kept the public spaces warm and the peripheral spaces were much cooler. These changes will likely be driven by fuel prices, so they are more appropriate where there isn't any natural gas available: houses where oil, propane, and electric resistance are the primary heating fuels. As of the 2009 EIA energy use surveys, there were almost 9 million households in the Northeast (New England and mid-Atlantic states) using those fuels as the main heating source. That's a significant opportunity. Last year, during November and December 2011, our net energy purchased from the grid was 98 kWh — that is, we imported 98 kWh more than we used. This year, during the same period, that figure was three times higher: 299 kWh net import. For one thing, it was cloudier. Generation of electricity directly from sunlight. A photovoltaic (PV) cell has no moving parts; electrons are energized by sunlight and result in current flow. system made 68 kWh more last year during this time.