I live in Central NJ and I have a 95% 100k btu input furnace for a two story 2800 square foot home. and basically the furnace is too big. I have it locked in first stage which is 65000 btu input and it is heating the house with no problem this winter (in 1st stage alone) even when the outside temperature dropped to 2 degrees. The installer would not give me a breakout but my total cost for the trane xv95 and a trane xL15i AC was $9600 - $1000 rebate = $8600 net and it included a TC803 thermostat and a chimney liner. I was told the AC is more expensive than the furnace so my furnace cost is something less than $4300 depending how much more expensive the AC was. I also had quotes from a local homedpot which was 5700k for the same furnace (before rebate) which is at least $1100 more expensive. I was also quoted from Sears and they were even more expensive (for the carrier version). Key1

From our experience with thousands of our fuel oil and LP customers, we've heard every story imaginable. The market is flooded with used car salesmen types looking to replace parts, replace systems and/or perform unnecessary service. Any stories the salesmen can fabricate, or any myths they repeat potentially puts money in their pockets. The inefficiency of all furnaces & boilers over time myth is funny. My favorite oil burner myth is that oil companies with service departments install larger nozzles to sell more fuel. LOL. Gas service people often tell oil customers that their systems drop dramatically in efficiency in a short period of time in order to make a sale. Most inefficiency we see is due to a combination of improper sizing, burner setup, zoning and system design including, boilers, furnaces, water heaters, indirects, ductwork, boilers, piping/pumping/controls and building envelope issues such as old windows, doors lack of insulation etc. Annual oil service consists of a cleaning, combustion test, filter change, nozzle change, strainer change, pump pressure test & testing safeties and general safety inspection, so It's not just about cleaning the unit. Besides servicing the heating equipment annually, you also make other safety checks plus other visual preventative maintenance observations as well. You check for or observe potential problems with combustion chambers, heat exchangers, boiler blocks, ducting, piping, wiring, leaks, air intakes, exhaust venting, roof jacks, powerventers, chimneys, aquastats, low water cutoffs, pressuretrols, circulators, valves, zone valves, indirects, control strategies, water feeders, expansion tanks, backflow preventers etc. Oil service techs are generally in customers homes on an annual or semi-annual basis, so while they're performing annual service they see more potential problems with other system components, (including gas fired equipment) as well as other structural and mechanical problems in homes. Because oil service techs are in customers homes so often, the preventive maintenance observations and human networking factor lead to a lot of other work, and referrals. Modern oil fired units are very clean, but they still need to be setup by a professional that performs a combustion test. I perform safety inspections and combustion tests on my own systems annually, but don't always clean them, or replace nozzles filters and strainers every year. One reason we see so many dangerous situations with our gas customers is that they never have their units inspected, serviced or replaced until the unit fails. We often get a call when the CO detectors have gone off, or when someone is feeling sick due to an exhaust leakage, blockage or cracked heat exchanger etc. Many people are unfamiliar with oil burning equipment, and don't have the knowledge, tools and parts to perform service and installations, so the market tends to be over-saturated with gas installers willing to work for very little money. This creates some dangerous situations combined with lack of combustion testing and customer neglect. Besides powerventers, there are direct vent boilers and now condensing oil fired boilers as well, although the majority of our customers use traditional chimney vented oil fired equipment. I think Olsen makes a direct vent forced air furnace as well.

Thank you Tigerdunes and Mike_home. Mike is right that I am trying to keep costs down. And a 2-stage 90KBTU new furnace will still be an improvement over what I have now. In answer to Tigerdunes' question about design temps - the contractor said it is based on maintaining 70 degrees at an outdoor temperature of 5 below zero. The contractor mentioned sealing the ducts by shooting something through them. He said it would offgas a smell like paint for about 20 minutes, which did not appeal to me. I don't want to be breathing a chemical spreading throughout my house. But perhaps I need more information. Can you give me a little insight into the sealing process? Is this a worthwhile option? A filter cabinet - the furnace is located in a small closet off a den. There is barely space for the furnace. I've been changing the filter for 7 years by bending down into that tiny space, and it's not a big deal - it takes me about 3 minutes. I will ask the contractor anyway, to see if there is any way we can fit a filter cabinet. The contractor mentioned with enthusiasm the Honeywell touchscreen thermostat (I believe, but am not certain, it is the Pro 8000, or in the 8000 series). He also mentioned the 9000, which he thought would be overkill for me. When I said I had seen some negative reviews on Amazon of touchscreen Honeywells, he said those are the DIY's you can buy on Amazon or at Home Depot, but the pro-versions won't have any problems. Do you agree/disagree?

A load calculation is indeed the right way. They're required in my state when applying for a permit for equipment replacement or of course initial installations for new construction. Can a calc be fudged or shortcut - of course. A real calc for an average home should require no more than 60-90 minutes in total. Laser tape measures make the work go fast. They measure ceiling heights, walls and windows and the orientation of all of them, assess construction type and quality and insulation, punch it in to a tablet and that's about it. Hacks will dispute the need if not required. "I know this neighborhood and have been in the business here for 20 years". Not all work is permitted. If the bidding contractor offers any baloney like this, call others. There are knowledgeable and honest folks in the business who try to do the best possible job using up to date techniques. Saying "if what's being replaced worked before, then that's the right size" is also baloney.