How many people in your household? Do you have any multi-head showers or large soaking tubs that you use?

Also, gas or electric?

Hi Jake,

6 people, lots of frequent guests. Master has large tub, yep, and multi-head shower. All electric.

Cheers

David

Since you are building this home, I'd design it for an 80 gal electric hybrid unless you are in a far northern climate.

That means providing headroom for the tank and also ventilation for the heatsink.

Hi,

I don’t believe there’s enough room in the crawl space to house one unfortunately.

Are there drawbacks to running hotter and using mixing valve?

So, @Redcoat Dave, I'm going to give you some grief:

You are not the first person on here here who is building a new house and the builder didn't think through the water heater. This happens on both low-end houses and expensive houses. The builder has been doing it this way for 50 years - or some such - and not going to do things any differently. Nevermind that the West is a 20 year mega-drought and global climate change is a thing... we will just keep installing an electric resistance water heater at one end of the house (in the garage) and a master bath with an 80 gal tub and 4-5 gpm shower at the other end.

We still have people in Texas installing water heaters on the outside of the house - what could possibly go wrong?!?

Electric resistance water heating is probably the worst way to heat water - and the most expensive to operate. But it's cheap to install -- and that's why it's installed in rentals and low-income housing. You obviously have the resources to do better.

You are building a home with 4.5 bathrooms! Tell your builder / plumber to figure it out and design something that is appropriate for the NEXT 100 years, not the PREVIOUS 100 years. This is THEIR job - it's not your job (or our job) to design your plumbing.