After wandering onto this site by accident, I have become more than a little amused. In particular, concerning the supposed low cost of operating a professional heating and air-conditioning company. I have firsthand knowledge of those costs. My small business has 5 employees. In FY06, our cost of doing business was over $340,000.00. That includes wages, office and shop costs, insurance (liability, theft, workmans comp, health and auto), automotive maintenance and repair, employee retirement, tools, licensing and permits, etc. That does not include the actual cost of goods sold. Any profit that is earned beyond that amount is at least deserved. Most companies extend a one year labor warranty on the equipment they install. If there is a warranty repair, they are not compensated by the manufacturer for their time. This is a cost of doing business that most people do not consider. If a thunderstorm comes by tonight, and knocks out a compressor, we will replace it tomorrow if the year warranty is still in effect. No, that shouldnÂt be covered but we are noted for going above and beyond. It has built an incredibly loyal customer base. Three of our six vehicles are specialty utility vehicles. These are not inexpensive to purchase, operate, maintain or repair. Operation of these vehicles with gas prices at $2.50 a gallon average $.79 per mile. I am certainly not complaining about my job or my business. I make a good living and very much enjoy what I do. However, since shots have been fired, I feel compelled to fire back. Though we purposefully avoid dealing in equipment as low in quality as the unit described, I have read through a GMC 90+ Installation manual before. Reading the manufacturerÂs written instructions are not an option for this engineer. Whoever heard of an engineer that did not read the instructions? All furnace manufacturers are very specific about the installation of the exhaust vent. Regarding length, size, termination and even number of 90 and 45 degree turns allowed. Additionally on the vent, I have only seen long sweep elbows specified. The point of the exhaust vent termination is critical as are the instructions for preparing the termination area. If the directions are not followed regarding termination, you have a high probability of damaging your home. As mentioned before, we do not install GMC equipment. However, I cannot remember reading any furnace installation instructions that did not specify using a manometer for checking and setting proper gas pressure/flow. The equipment we install is very specific about transitioning mismatched sizes of furnace and indoor coil. It is obvious sir; you either did not understand or did not thoroughly read the instructions. My impression of an engineer that is earning in the mid 80Âs is they must be an underachieving, 9-5 cubicle dweller. I have been a registered PE since 1989. I think you must drive the choo choo. We are definitely not the same kind of engineer. To my knowledge, all HVAC equipment manufacturers warranties are void if the equipment is not installed by a qualified, trained HVAC professional. Your plumber looking at it after the fact does not qualify. However, manufacturers are too lenient about warranties. They will probably give you the parts that might be destroyed due to improper gas flow or improper exhaust venting. However, if something serious happens, like burning down your home or soot damage, your insurance company will want a licensed insured company to sue. Since there is not one, they just will deny the claim. My free advice here is to find an exceptionally qualified company to double check your installation. I am sure they will charge beyond what you think is "reasonable". However, you have stepped into an abyss that is beyond your comprehension.

Thanks so much for the comments. Baymee - yes, they are talking about installing a Field airboot kit and power venter. Stu - we can't run another line through the roof. It would not be in compliance with building codes to reuse the same hole through the house (again not sure about termanology)because there is no where to support the line and it would hang as deadweight from the roof. There is not really another good place to run a vent pipe from the crawl space up through the house to the roof. Don - I have no concept . . . what does a new high efficiency condensing gas furnace cost? Our furnace is older, but in good shape. Thanks again for your help!

Mike, that's probably good advice, as it's the standard recommendation. But Gravity Heat does come with certain advantages, which from a certain perspective, outweigh the negatives: 1. Fuel Adaptability: in its lifetime, ours has run on wood, coal, oil and gas! If current trends towards economic instability and increasing resource scarcity continue this alone makes our "octopus" very attractive as a second furnace. 2. Dependable: few moving parts, strong long-lived materials, little to go wrong. 3. Ecological impact of embodied energy: As an annualized impact, this equipment's ecological footprint is tiny, even assuming large efficiency improvements, an honest evaluation including the embodied energy of new ductowrk, etc. makes it unlikely that furnace replacement would "pay off" in the lifetime of a furnace. 4. Financial viability: again, assuming huge efficiency increases only possible with home alterations that are likely to have a negative impact on the lifespan of our victorian home---and not including those costs in my calcualtions--a new furnace is unlikely to pay for itself over its lifetime! When I do the math, the payback time ends up being over 40 years, not including maintainance and parts replacement! 5. Depressurized heating efficiency in an old house: lab tests of efficiency assume the relative air-tightness of a modern home. In a leaky victorian home, there are efficiencies that come with not having heat "forced" out of the home by a blower. 6. Reasonably Upgradable: efficiency improvements can be made such as updating the ignition, adding thermal mass, and installing radiator coils in the flue pipe, which was popular in the 70s and can capture 40-50% of the "lost" heat, bringing efficiency into the range of modern heaters. Unlike a new furnace, these improvements would pay for themselves in a few short years. So, it's not necessarily "cut and dried" and there are good reasons to "drive it into the ground" that you don't typically hear.

mike_home: my heat pumps are 4 ton units each; I went with slightly oversized air handlers. callights: Thanks for the tip on water temp, I will check on that, too. FYI, not sure if it's a clue but I am using the boiler for home hot water (showers) via indirect zone, and the boiler is maintaining I 150-170 degrees when the hydronic calls. HVAC support were prompt and helpful via phone; I told them to hold off sending someone onsite until I've gathered more data (plus they were dealing with folks who had NO heat last weekend, much worse off than I). With respect to gathering data, here's the latest: I've ended up setting the hydronic cfm to 1350; at that it looks like the system can maintain house at 68-70 if I wish...although wouldn't you know it the temp is now 50 degrees higher here in New England! Guess I need to wait for next cold snap for next test, but I suspect it's still not calibrated perfectly because it did seem to have trouble getting up over 70 degrees that cold day (after the cfm increase)...and no, I don't want my home at 72, it was just a test to see if hydronic could make that happen. Should I worry if it can only get up to 69/70 on a sub-zero-F day (as an indicator of some issue)? The VR1-40 is rated at 120-140K BTU, surely that's enough for a house my size?