spray foam in rafters for an unvented attic..it is an option. it allows the hvac contractor to do a regular install instead of configuration of fur downs/trey ceilings etc. but...unvented foam sealed attics are Semi-conditioned, not conditioned. the ambient temp & temp inside of the foam sealed attic are usually within 10 degrees of each other. and, the tradeoff for spending 3x the cost for foam is smaller tonnage hvac system. so hvac co needs to be on board. using foam covers a multitude of building problems..oversized holes for plumbing & electric. IC instead of ICAT recessed lights, oversized cuts at bath fans, stove vents, fireplaces not sealed off in attic and thermal bypasses all become non-issues when the air & thermal barrier is moved from attic floor to roofline. as we put more efficient hvac equipment into attics, we have to be careful. these units produce colder air (our issue in summer) and plenums condnesate in an vented attic. this is one of the reasons that foam has become such a strong product, because now the attic isn't as hot, and colder air in the plenum doesn't cause as much condensation in foam sealed unvented attics. I'm trying to get my page online for videos up and running. I just uploaded video of an open cell foam install. the videos show how to seal the roof to attic floor (soffit/eaves) connection properly, how to seal at passive turbines on roof (for existing homes) and the last is after rafter bay has been foamed, how to come back & fill in voids & low spots. later this week I hope to have time to get it up and ready for viewing. drop me an email & I'll share the link. I'm getting pros & cons as to making it open to public...which I'm inclined to do...but have gotten feedback against it...so for now..you'll need a password. as a homeowner you have to be very selective in chosing a foam company. it isn't the owner/salesman that makes a good install, but the person doing the install. if they rush...they miss areas, if they move too slow the job takes longer. temps of mix,combo of chemicals, roof temp & moisture content all have to be consitered. I'd expect to see pictures of previous installs, be allowed to go on a job to see the process & to be able to call previous homeowners to see if they achieved savings & comfort after the install. ..yeah...I'm picky! but I've seen some really bad installs over the years. finding a good company, with an experienced installer...takes time. as I test the air tightness & measure the depth of the install, companies locally know that they have to meet my standards. here in La., we use open cell foam...what is the type for your area...open or closed? if you go this route...interview companies. make sure you know going into it that you still have to meet the code requirements for R-values. with closed cell at R-6-7 per inch & open cell at R-4 per inch..the right amount of inches have to be installed. the whole 2-3" 'performs as' is hogwash. 'average' fills are hogwash. you want an install with no dips (low spots), no voids or gaps & a good seal at the attic floor/rafter area so that no hot humid air enters at soffit area of the house. I'm attaching a picture of a good install of open cell. note that the rafters are 2x6 and are well filled between rafters , faces of 2x's are covered. the bid was for 7", but at lowest point the foam is 7" thickest point closer to 8". note the soffit (roof to attic floor) also. this is what is necessary for air seal of attic. fwiw..the company that did this install, the owner is the installer. in my part of La., these seem to be the people you get the best install from. not so much with salesman selling job & installer doing the job. best of luck.

I'd do the 14.75/9.0. But what is the efficiency of the NG component? I have a 90% because of a basement location - it was actually cheaper. I have been in the house 3 years and have used about $500 in gas so the 80% would probably cost $15 a year more to run. (5000 sqft house) You should know that "energy rated" does not at all mean that the house is being built with best practices. My biggest regret is not doing a better wall system - just adding an inch of rigid foam would really futureproof your house but payback is likely 15 year range. Of course, dropping to seer 13 and using the savings here will be a better long term financial decision. With NG costs right now, it is really hard to justify much $$ invested on the heating side without a long outlook. Mature trees are nice but you can get window coverage pretty quickly with planted trees. Sounds like West is the front. What I find works well is a flowering tree planted fairly close to the house centered on a window bank. You can crop the lower branches as it grows so the window view is not blocked and the house is still visible - but within a few years, you get a great reduction in the heat gain from that window bank.

The biggest problem with HVAC zone systems is knowing when to choose it as a solution and when not to. Some HVAC companies it's about "sell, sell, sell" whether or not it works... there's more money in "sell, sell, sell" --- when it's only about money? So does the comment above mean I do it for free? No. If you think that you are reading things that aren't there. New construction? best to choose separate systems 9 times out of 10. In order for a zone system to work, you have to know what you are doing. Most HVAC companies staff (the techs they send you) are 20-30 year olds. How much practical experience could they possible have? It's best for HVAC zone systems to be an elegant solution. A HVAC zone system is a tool in the tool bag. Not all homes are suitable for zone systems. Some homes there is no other way, and in some cases complications to those problems will make an HVAC zone system design possibly more prone to problems. You have a problem now, do you want more problems. These decisions among others are decided "in person" --- so considering that becareful what information you decide upon from the internet. Just because it's here doesn't necessarily mean it's true. That said: Depending on equipment level chosen, how many different floors you have in your structure, how much room you have available... will all be factors that make you decide one way or another. From there it's in your best interest to pick a contractor that is skilled: especially when it comes to HVAC zone systems. (there's a lot of garbage out there.) (click to enlarge if necessary) I service the Katy, Texas area.

Wayne, The Goodman furnace model you posted is a top of the line Modulating gas furnace also according to what you posted it is replacing a 100K 93% gas furnace that is 20 years old. Modulating means this top of the line gas furnace will modulate based on the heat load needed to heat the home. The homeowners that are suggesting you to reduce the size of this furnace are doing so without running a heat load calculation. (They often tell you to do this --- but they never practice what they preach.) Nor are they taking into consideration that your current duct system is probably sized for a 100K BTU furnace. So you put in the 80K BTU furnace without addressing duct work etc... nothing but trouble. (20 years is a long time to run a *supposed* over sized furnace----- if it doesn't make sense? You're in the fiction section of the internet.) If this were a new home build in 2020, yeah an 80K BTU furnace *MIGHT BE* the better choice. Amana top of the line model is: AMVM97 Thermostat: I would stay away from the Nest. Other than that either the Amana or the Goodman can be controlled with any off the shelf thermostat. If you want to control it from your phone I would suggest pairing it with Honeywell stat that works with Honeywell Redlink. Your HVAC company should be able to set this up for you. Either the Amana or the Goodman (top of the line) furnaces are good choices for your climate. Modulation of these start in the 60,000 BTU range and gradually heat up as the load dictates. As cold as your climate gets I would go with the 100K BTU model ------- you've got 20 years under your belt with the old one. How much more proof would you need on sizing? If it's on the internet it must be true? yeah we know how that turns out......