HH: I am no expert by any means, just a homeowner trying to get heat out of his masonry fireplace. I have experience with only one insert - my own. Here's my best shot at your questions: "Would glass doors prevent the cold house effect?" Yes, the glass doors would prevent the cold house effect of an open burning fireplace by eliminating the excess combustion air that is consumed by the fire. "Is there any way to get heat out of the fireplace with closed glass doors? Does enough heat radiate off closed glass doors to heat a room or more?" The problem with getting heat from a fireplace with closed glass doors is the glass itself. Most glass doors are made of tempered safety glass which does not allow UV rays to pass through and provide heat. This is why I made the comment in a previous post to possibly combine the grate heater with a set of glass doors. The glass doors in most quality inserts are made from ceramic glass which allows UV rays to pass through. Some glass door manufacturers use ceramic glass, but it can be very expensive. I do not know if a set of ceramic doors would provide enough UV energy to heat a room (I wouldn't think so, but it's just my opinion). "Why does an insert heat better than just glass doors? Afterall, the insert needs to draw the house's air too. And it is just a firebox in a fireplace which itself is kind of like a firebox". An insert heats better because it is made to extract heat from the fireplace (the glass doors alone are made more for looks or when the fire is burning down to prevent smoke from coming back into the room). Similar to a set of glass doors, it controls the combustion air for the fire by providing just enough air to feed and maintain the burn (an adjusting lever controls the intake air flow). The insert eliminates the excess combustion air that makes a room cold since cold outside air must replace the excess combustion air. As previously noted, most quality inserts use ceramic glass in the doors. Most inserts have at least one fan that draws separate room air into the non-combustion passages of the unit, circulates the air around the passages, heats the air, and sends it out of the discharge vents at high temperatures. Inserts that do not have a fan rely on natural conduction from the hot surfaces of the insert to release heat into the air. Inserts that are EPA-certified also have a "post-combustion" zone which further burns the gasses from the wood to provide a cleaner burn and as well as additional btu's compared to burning only the wood. Last year, I measured the temperature of the heated room air from the discharge vents of my insert using a multi-meter with a thermocouple attachment. I measured a max temperature of 348 degrees F at the vent, 280 degrees F at one inch from the vent, and 148 degrees F at two inches from the vent. I get decent heat out of my unit. "What makes an effective insert? Should it be made of cast iron or steel? Is the insert with a bay front a better design than the flat front because it has more radiant area?" I only have experience with my own insert so I don't think that I can provide a good response. Maybe you can make a separate post for this question. I would want a variable speed fan that is fairly quiet. My fan can run in "blow dryer" mode if I choose to but it is fairly loud at blow dryer speed so I keep it at medium speed. I think that the bay front may add more room to the firebox (not sure about this), and may provide a surface area to keep a pot of water so that humidity can be added to the room (plus more surface area as you noted). It is a nice look but you need additional hearth floor area under the bay. I hope my answers helped you.

Post your electric rate in cents per kw-hr, and your gas rate in either $ per ccf or $ per therm. The heat output of a gas furnace is very similar to electric resistance strips if enough kw are used. Utility costs decide which is cheaper. 5 kw electric strips put out air temps about 15F greater than room temperature. So a typical 10kw strip heat puts out 100 degree air if the room temp is 70F (70 + 30 = 100). This# is based on 1200 cfm air flow from the indoor fan. 15kw = 115F which is more in the range of gas furnace temps. The air handler must be sized to handle this heating load. These temps are for the strip heat only and do not include any btu's from the heat pump. The heat pump itself puts out air temps from about 90F to 100F based on outdoor air temps. The 90F supply temp air from the heat pump combined with 20 kw aux electric strips provides minimum 120F output air when needed. Heat pumps provide enough heat up until the balance point, which is around 32F or so based on home construction/insulation (mine is 25F). At temps lower than the balance point, aux heat is needed - either furnace or strips. The good thing with the strips is they can run along with the heat pump. The furnace cannot run when the heat pump is in heating mode; its one or the other. When the heat pump goes into defrost mode, the air output is in the low 50's. 10 kw provides 30F to temper the air into the low 80's so it doesn't feel too cold while the heat pump is defrosting. The furnace will provide 120F air during a defrost cycle. The heat pump is typically 300% efficient down to 35F ambient. Heat pumps make cheap heat. One comment about the XP-19. It's "up to 19 SEER". Not all combinations get 19 SEER. Model numbers can be used to determine actual SEER. Also, dual-compressor systems like the XP-19 are more for hot and humid summers than for heating. In the cooling mode, running on 1st stage saves $$ and reduces humidity. Once on 2nd stage, it loses its operating $$ benefits. A 14/15 SEER usually provides the best combination of purchase price and operating cost. If you can afford a "19 SEER" system, go for it. Whichever SEER you get, you want as close to 12 EER and 9 HSPF as you can get for low operating costs in cooling and heating respectively. Good luck.

Okra, that wasn't last year but ten years ago in 2005. When I constructed a canopy tunnel within my 30 x 96' high tunnel and then put row cover over and under that canopy. The row cover under was supported by wire hoops and I also had about 50 gal. Jugs full of water placed around plants; BUT NO SUPPLEMENTAL HEAT. The majority of the plants lost were along the edges and ends of the rows. I believe that cold spots developed when temps dropped below freezing. It's 37*F now at noon and snowing so I'm grateful to have wood heat to keep plants growing. And here's my secret that I will reveal- You can keep plants alive under most conditions with just row cover but if you want then to GROW you need to keep them warmer at night ( and some days).

Thank you all for your comments. I do have a "master" setting on the main duct leading from the furnace that has a summer and a winter setting - this makes some difference - and there is a return air vent upstairs as well as on the first floor. The energy audit representative discouraged me from completely closing some air vents (like on the first floor). He said the system was designed for air flow through all ducts. Two zones/separate a/c units would be optimal but not sure I want to put that kind of money into solving the problem. But the heat pumps in my development seems to starting to fail so, when mines goes and has to be replaced, I will investigate potential solutions with two zones. At this point, for the bedrooms, I'll go with good insulated drapes that I will keep closed in the summer. For the window above the door, I finally found someone knowledgeable about shades (at my local Lowe's), He showed me a double cellular shade that will be included in a 40% off sale in February. A motorized shade will be in the $250 range plus installation. I used Lowe's for all the windows in this house and my last one and been very satisfied. The only issue now is that the motorized mechanism has batteries housed in a unit in the shade header. This will be 16' above the floor, so replacing batteries is going to entail my handyman coming over (I'm 70 and don't do ladders!) with at least a 12' ladder when this is needed. Thanks again for all the good thoughts.