Wow. Ok. Where to start. First and foremost the SHEET vinyl is the only one that can brag about water proof. If you have leaky pets or leaky people, this is the go-to product if water PROOF is a requirement. Sheet vinyl requires a professional install which is normally quite reasonable. The costs grow with the subfloor PREPARATION costs (where are a separate line item that may not have a "final total" until the job is complete). The click together vinyl planks are all the rage right now. Some are DIY friendly - but most are quite picky about technique and take +++patience to learn how to do it right without breaking the click-edge. It is possible to do this yourself....but it requires an understanding that you will have a STEEP learning curve. Be OK with that. The cost to install the planks is a little bit more than laminate flooring. Again the costs go much higher once subfloor preparation is added in. Again, this is a separate line item that, as above, might not have a final tally until the job is complete. The "flatness" quotient for vinyl planks is extremely important and can be considered outside the comfort zone of many long-term DIYers who have tackled several different projects. Again, it is possible to DIY....but it takes quite a bit of time to learn the skill/trade. A professional can have most of this done before you have figured out how to work the self-leveling-compound (which is not self-leveling BTW). Is there anything else that you were looking at for information? I've just touched on the two biggest differences between the two products. I didn't know how much info you were looking for.

So after a lot more research, I’ve elected to paint the floor with Wise Owl One Hour Enamel. Plus primer and a sealant. It’s possible I may add a crackle glaze between the first and second coats of OHE, with a darker paint color over a lighter one, then seal, then use a brown glaze to softly define the grout lines, then seal again. I found lots of great info through White Owl suppliers & users. The OHE is super strong & durable. But this is still in the thinking stage. I’ll be doing some experiments, then decide. And if I want a rug/rugs in there, I’m going with Ruggable washable rugs. Thanks for all the advice & comments here. Love the internet!

What I'm hearing about the husband wanting something different = different colour. That's easy enough to do. When lacing in a new wood floor, the ENTIRE wood floor will be sanded and refinished. The colour you have NOW will change (as per your hubby's wish) by the end of the project. Excellent. Win-win. If you leave the existing hardwood IN PLACE you will save the cost of material + cost of labour to remove it. So part of your $16K budget will be minimized by $1K - $2K. So far so good. Currently the vinyl sits LOWER and the carpet sits HIGHER than the hardwood. That's GOOD! That tells me your floors could all be sitting on the SAME subfloor. That's could mean a cost savings (no one will know until the vinyl comes up and the carpet comes up). Or it could mean nothing at all. Subfloors under 'sheet' goods can be horrible. Especially under carpet. Carpets hide HORRIBLE subfloors (that's why builders like to use it...it saves them TENS of THOUSANDS of dollars during a build). If you choose to remove EVERYTHING you will most likely be looking at subfloor repair/replacement. Again, NO ONE will know until everything is down to a continuous layer of subfloor. At that time, the HIGH-END flooring professionals (who deal with hardwood day in and day out....no "guy with a hammer" need apply) will evaluate the subfloor and decide (at the time) what is required to install a hardwood floor. At that time you will be given the ACCURATE quote for the subfloor and labour costs for that portion. Until then you are flying blind re: costs for subfloors. In my neck of the woods (Vancouver BC Canada...just a little north of you), subfloor prep runs $2-$3/sf when dealing with carpet/vinyl removal. Sometimes it is less...sometimes it is more. But that's the normal ball park. I vote for keeping the existing hardwood and adding to it. It will be the cheapest option by far. To give you an idea of costs for refinishing what you have = $5/sf for a full sand/stain/refinish. You can do a quick calculation of the square footage of what you have and then multiply it by $5/sf. It is CHEAPER to refinish hardwood than it is to rip it out and replace it with a factory finished product. Try to convince hubby that he can get the "new" that he wants even if you keep the old. At 19 years of age, your hardwoods are looking for a sand/refinish in the next 3-5 years anyways. Now is a GREAT time to lace in some of the SAME wood (same species/cut/width) and redo everything all at once. Your timing couldn't be better!

With hydronic radiant systems, in order for them to be more efficient, you want the return water to still have a little heat, but not too much. I wonder if your carpet is keeping the heat from dissipating while it traverses the loop, resulting in hotter return water. Sounds like LVP is out, because you can't heat a home if your boiler is set at 85, but you might want to bump it down some anyway to account for the lesser amount of heat the loop(s) seem to be losing before returning to the boiler. Old oil boilers were at around 180F, but newer more efficient gas ones are more adjustable and ours is set at 140F most of the time, in a pretty mild climate. We do bump up the temperature to as high as 180 when it's 20F or below outside. The efficiency depends on the temp of the return water, so you could save some money by bumping it down. Good luck.