Architectural Designs

Should I replace my oil furnace or buy a heat pump?

I live in southwestern VA and we have cold winters. I also want air conditioning and have heard I may still have to use a window unit in the upstairs bedrooms. I'm afraid the heat will be cold and the AC will not cool. I am planning on only one unit for a 2 story house. Also, is there a difference in metal ducts and fiberglass ducts? Thanks!

Public Comments

1. Yes, replace it with a heat pump. But I'm really confused why you don't think it will heat or cool your house? I live in Arizona and we use heat pumps. Almost all new homes have heat pumps and it cools my 2 story house very well in 120 degree temps. Just make sure you get a big enough unit.
2. You can mount an air conditioning unit to an oil-fired forced-air furnace. A split system A/C will do, there is no need in this case to use a heat pump unless it is calculated that it will cost less to run then using oil for heating. In some cases it is efficient to use a heatpump with a fossil fuel kit that will turn on the fuel furnace when the temperature drops below the efficiency range of the heatpump. The key is to have both the equipment and your ductwork sized properly to get the proper amount of air to each room in the house. While fiberglas duct may be slightly less expensive to install, the metal ducting will give you much better airflow with less static resistance and much less particulates in your air. The metal will also be more durable and less likely to become broken or small animals chewing it up. Fiberglas "ductboard" is okay for some jobs but in my opinion, shouold not be used in residential applications. A reputable contractor will do a load analysis on the home and give you a report showing the proper airflow required for both heating and cooling loads in all rooms of your home. You may inquire about splitting the home into 2 zones with seperate thermostats since most likely you will only be spending your sleeping hours upstairs. The possibilities for a good design which maximizes comfort and energy savings are many. Research your options to get the best system for your $$$. Consider a humidifier on the system and a high efficiency (not electronic) air filter installed and make sure the furnace is a brand name like Carrier, Trane, Lennox, etc., with a good warranty and that parts are readily available in case of a breakdown.
3. No do not replace it with a heat pump. Heat pumps are only efficient until the outdoor temp drops to about 42 degrees, after that the heat strip will kick in and cost you a fortune to run. Heat pumps are best in warmer climates.
4. Heat pumps are fine for places where it doesn't get very cold, but they don't put out all that much heat. When I lived in southeastern PA I had several friends who had heat pumps in their houses and their houses were always cold.
5. If you are talking about an air to air heat pump (the type with a box outside that looks like a large air conditioner), it will not replace your oil furnace, but it will supplement it. The AC will work as well as, or better than, a normal air conditioner, so you will not need supplementary air conditioning, but you will need supplementary heating. Air to air heat exchangers pull heat from the outside air to help heat the house. If it is too cold outside, they do not work well. It would heat your house in cool weather, but not cold weather, and the savings would probably pay for the cost of the unit over a few years. The type of ductwork does not make a significant difference. I have a ground source heat pump. It pulls the heat from underground coils. Since the temperature of the ground below the frost line never drops too far, it works all year. I live in central Ontario, Canada. The coldest I have seen since I moved here was ten days where the temperature never rose above minus 40. The heat pump kept the house warm, and the supplementary heating never kicked in. The problems with this type of heating are the initial cost, and the need for oversized or extra duct work. The heat pump does not heat the air as much as an oil or gas flame, so you need to move more air. This works well, because there are no cold spots in the house.
6. A heat pump is a very good efficient unit. The only drawbacks are if it gets down below a certain temp, the heat pump is ineffective and it goes to an auxiliary resistive heat mode. Also, if you're used to turning up the thermostat and getting a big rush of hot air to quickly heat up a room, you won't get that with a heat pump. You should also compare electrical rate prices with the price of heating with oil to see which is easier on your bank account. Fiberglass ducts are less labor intensive to install than sheet metal ones. I don't know about actual cost comparison though. It's very hard to retrofit an existing structure with ductwork. Not impossible, just difficult.
7. An air to air source heat pump is a good bet in the country where you seldom fall below freezing, like in the Southwest or pacific northwest. If you have freezing conditions much of the winter then a ground source heat pump would be your best bet. You also need to know total costs upfront and how much per therm each heating source uses, when looking at oil versus a heat pump. Then you need to weigh the cost of the new system to a return value of how long you will live in the home. Call you local power company, most will do a comprehensive analysis for you to show you which is best for you.