I think the rheem quote looks good. If its 8-grand less thats a major reason to go with that quote. 95% efficient 2 stage furnaces are plenty comfortable and efficient. A good thermostat will make it run in the low-stage most of the time. True modulating or 3 stage furnaces are more comfy but maybe its overkill. Just make sure your not oversized. Remember 95% efficient furnaces put out 15% more heat than the same size 80% efficient furnace. FYI - those rheem A/C's in the quote are plenty efficient also and RHEEM makes good quality stuff I think.

Here's my quote for a 4,000 sq ft new construction. Our HVAC size is smaller beacuse we're doing spray foam, but the main floor HVAC is oversized to handle the basement of 1,600 sq ft that we'll finish later. Main Floor Lennox G61MPV-48C--090 90,000 btu 2 stage variable speed gas furnace Lennox XC16-048-230 4 ton 16 SEER 2 speed AC Condenser Lennox CH33-42B-2F 4 ton Cooling Coil Lennox HCWB2-17 Bypass Humidifier Lennox ERV Energy Recovery Ventilator Second Floor Lennox CBX32MV-036 3 ton variable speed air handler Lennox XP16-036-230 3 ton 16 SEER 2 speed Heat Pump Lennox ECB29-10-P 10kw Strip Heater Overall Filter HEPA-20 Lennox Zoning Kit - Second is two zones, Main and Basement are independent zones. Also installing a "summer switch" for a main floor guest bedroom. $25,000 for everything. The HEPA was a $1,100 option. I would think that you can find a quote between $10,000 and $15,000 with the Rinnai included. New construction ductwork is running around $2 per sq ft around here, so that's a good chunk of my quote. And if you're zoning, I'd opt for dual stage and variable speed. I'm no expert, but I understand that those features work very well with zoning to prevent short cycling. And when a contractor gives me sass, I don't hire them. The first HVAC guy from our GC didn't want to downsize the equipment, regardless of the Manual J calc. He won't get my business. This quote was from a Contractor that took the time to answer my questions and advise on issues we had. The "summer switch" was his idea because that bedroom is too small to be it's own zone off the main floor. We wanted floor registers for first and second floor, but he explained that running the HVAC through the second floor would be a huge expense and decrease efficiency (lots of turns in the ducts). He said that we'll try some different ceiling diffusers to make sure that we don't have air blowing directly down on us in a room. If the install goes half as well as our conversations, I'll be refering him to everyone in our location.

your hvac systems are oversized. all bids come out to about 400 sq ft per ton. hugely oversized for a well sealed house. where are you putting the foam insulation? better than filling stud cavities in walls, using 1" foam sheathing to exterior, conventional insulation & airtight drywall approach to interior is a better more affordable high performance wall. save the foam for the roofline & make sure that inches = R-value for your area (R-38). no "performs like" R-38..inches = R-value. you need a load calc, seriously. there is a guy fairly close to you who does load calcs, blower door & duct testing & has ties for foam insulation company. drop me an email & I'll share his contact info with you. don't pay for oversized equipment that will run in low speed 95% of the time. take the time now to get units sized based on accurate inputs into load calc. ductwork is in foam insulated unvented semi conditioned attic correct? paying upgrade from R-6 to R-8 isn't much...but may be beyond what install crew has worked with. not a huge issue, but you'd be surprised how they whine & moan over stupid stuff... just fyi other posters...code for La. is R-6...not R-8. crazy, but there it is. and OP, take a look at Slemco's Design One new construction guidelines. best of luck

Insulation looks rather easy by principle but you have a myriad of things in an attic that if done wrong will not measure up fully. Your house is a shell and the thermal barrier of that shell is what keeps radiant heat out. Heat is energy and attracted to cool... radiant heat doesn't flow from hot to hotter. Insulation is a dirty, scratchy nasty job. You will be forced to put your body into positions best left for that of a horror movie. Toward the eaves of the house you will be challenged because there isn't much room and sometimes the eaves extend outward a good distance. If you mess this part up the value you are placing on the insulation project that hasn't been done will not live up to what you think it will. The AC company will then get blamed for your handiwork when the AC can't keep up on the hottest day of the year. Realize I've been to homes with thermal barrier problems of someone who thought reinsulating the attic was an 'easy' job.