House: Dayton Ohio area 950 square feet 1954 brick ranch with plaster walls, blown in wall insulation, attic R-39, double pane window/tight wood storm combo, unfinished basement. 90 percent of sealing done, basement band joist R-13 coming with R-10 4' wall drape to below grade. Attached garage access to basement and attic, no access in conditioned space.
Heat loss: measured 19K recently on a 5 degree day (which is also design day temperature). A professionally done calculation using Wrightsoft before I upgraded the envelope estimated 35K heat loss on design day.
Existing AC: circa 1995 Janitrol two ton.
Existing duct: Metal, Ductulator calculated capacity 850 CFM. Supplies in five rooms (kitchen, living room, two bedrooms, bathroom), returns in four rooms. This install removed one unnecessary supply to living room to better balance room temps.
New furnace: Bryant Evolution Plus 90i (355AAV) 40K two stage 96.6 AFUE output 25/37K. Identical sister model is Carrier Infinity96 40K two stage.
Thermostat: Bryant Evolution Control (SYSTXBBUID01-C)
Water heater: Navien NR-180A 15/150K modulating 98% efficient condensing water heater, 3" PVC vents.
1. System view, condensate pump. 3 condensate lines running into pump (half gallon tank) from the furnace, AC, and tankless condensing water heater. You can see the trap for the AC behind the floor support. Pump discharge runs overhead to sewer line trap.
2. Filter rack view. This is the other side of the furnace. Standard Carrier/Bryant 4" media. Because of the new furnace configuration, the final return drop had to be reduce to fit. The main trunk was way big at 1,200 CFM capacity so the reduction was harmless. Note the canvas transition (closer view in photo #1).
3. Vents, furnace condensate line. The 2" vents terminate in a concentric through outside wall. This furnace has an internal condensate trap.
4. Navien, brine tank. The Navien is mounted on the original chimney that serviced the original natural draft furnace and water heater, and its huge 3" vents run through the chimney to the roof. The very hard water in my village water system requires a water softener to extend the service intervals on the tankless heat exchanger.
5. Water filters, softener. The hard water and old pipes of the village water system require frequent system flushing through fire hydrants. This photo shows the clear washable pre-filter to catch debris, and the blue holder for a large charcoal water filter. This has completely removed the noxious chlorine smell from household water and the water tastes great. The green tank is the resin bed for the softener. Custom built on demand softener, the recharge brine goes into the same sewer line trap as the condensate pump.
As part of the infrastructure redo, and to prepare for optimal basement insulation installation, the original galvanized and copper water pipes were completely replaced with the white PEX you see in the photos.
Installation notes: Both the tankless and the furnace install took two days. Esthetically, I think they did a really nice job. While I had some input (especially with my plumbing layout which was not done by the HVAC company), they were much more professional than my expectations and needed. I was quite surprised when one tech pulled out a pocket level when he installed the stat (I was going to suggest it if he hadn't). On questioning him, it turns out that the company trained him that way. New company techs don't even do scheduled maintenance by themselves for three years.
No way to tell from the sales guy how installers are going to do their job. So I feel like I lucked out with my choice of companies, and how their culture demands professionalism from their install teams. It wasn't all roses though.
Perhaps they didn't do as much as the most professional companies I have read of here. They did measure gas pressure in both stages, but no combustion analyzers, separate CFM or air flow measurements, or other diagnostics. They did not do any other diagnostics that I caught them at.
The Navien installer left without verifying performance. This model has a half gallon internal tank and circulation motor eliminating the cold water sandwich effect, and works with a faucet minimum flow - most tankless require half gallon per minute flow. Turns out that it was not set up right from the factory, and I had to call Navien to adjust dip switches to enable it.
Still, overall, I'm pretty darned happy with how the install came out.
External static performance: The Bryant Control reports low stage is 483 CFM and .21 static, high stage is 700 CFM and .46 static. The reported static is very sensitive, if I close the bathroom supply, the static bumps up .03.
Heating performance: I may post a separate review of the furnace (and tankless) so I don't intend this to be a complete review, more just an install report. That said, the lower BTU output and the minor duct modification have balanced my room temps to within one degree. No need for an always on circulating fan, or even to adjust dampers (two minor register adjustments only).
In contrast, the Janitrol 80K furnace (~ 60K output) that was briefly in the house when I bought it two years ago before it broke had a room imbalance of close to 5 degrees. I was able to bring it down to 2 degrees by closing the kitchen supply most of the way, and completely blocking one living room vent (now removed).
The "free" WeatherKing 60K 92% that replaced the Janitrol moved the room differential back up around 4 degrees. I could get it back down to about 2 degrees by running the PSC fan all the time. However, it proved to be more comfortable to live with the 4 degree differential than the draft from the fan.
Noise: Pretty quiet on low stage where it spends all of the time absent a setback. I can tell it is running, but it is quiet enough. It is really a wash with the original Janitrol - a little quieter, but the frequency is not as pleasing as the deeper toned Janitrol.
Much quieter than the WeatherKing - which was probably blowing 800 CFM.
Some transformer hum started on day three (yesterday). Coincidentally, the WeatherKing also started humming on day three. I fixed the WeatherKing by unbolting the transformer. I will call the installing company next week to see if they can do anything before I try it.
Thanks! I lurked here for a year learning what I needed to know to make a wise equipment and company choice. If I had decided on equipment and a company based on just the quotes I received over a year ago, there is no way I would have ended up with a system that performs as well as this one. In fact, the furnace selection is a bit obscure and the local distributor doesn't even stock it. But I learned here that it suited my house and personal preference the best and found a good company to put it in.
Looking forward to seeing what everyone thinks of the install!