GC-ing my own home: Plumbing & HVAC?

[maxpower]

Hey all,
I'm general contacting the construction of my family's next home. We paid off our last home and now are living with my mother while we build. I just got my designs back from the drafter last week and I've begun the bidding process.

Just got my first plumbing & HVAC bid back from one of my plumbers on Friday. It blew me away! $46,000!!! Our home is 24x30' and 3 levels (see attached). We live in Minnesota. I was thinking of going Mini-splits (Mitsubishi Hyper Heat) with in-floor radiant heat (water) in the basement floor and a wood burning stove on the main level.

I feel like I'm in a bit of a pickle in that I have no way of knowing whether or not this guy is over-building the system or not.

Also, I shudder at the thought of paying his mark-up on all this tech in addition to the labor costs.

Is it feasible for me to buy the Mini-split system and boiler on-line and simply hire a plumber to install it?

Anyone have experience going through this process?

[mjones1234]

I went through the process a few years ago. I have a two story home with 2112 square feet. I paid a guy to install the HVAC, run the ducts, etc., and the total price (Rheem system) was
about $5200. The plumbing I paid a guy to do the rough in, but then handled all of the sink/toilet/bathtubs, connections etc. from there. I think the total cost for the rough in plumbing was $2k with labor and PVC. I did the same kind of situation with the electrical, but paid a few guys to pull the wire as that can be a pain in the a$%. Then, I did all of the hookups at the service panel, attached outlets and switches, etc. This cost me in the neighborhood of $1200 plus the wire, outlets, switches. Of course, I live in an area where there are no building inspections. So, I'm not sure that the work I did myself would be legal in a more bureaucratic area. The price you were quoted seems high. Move to Alabama. It's cheaper in the South!

[Tjat]

That seems pretty high, especially for a new construction build where all the work is easy to access. I think the only option you have is to just get additional quotes. Unfortunately, you're limited by the market rate for certain tasks.

As far as buying your own equipment, it's up to the plumber. I generally refuse to work with contractors that insist on buying all equipment or worse, refuse to provide a split of labor vs equipment. They hide behind their warranty but everyone knows it's so they can mark up the prices.

[pbkmaine]

Get multiple bids using recommendations from friends and places like Angie's list.

[jda1984]

Fellow Minnesotan.  $46k sounds really high.  I'm not familiar with the mini-splits system, but a typical forced air HVAC install without A/C is going for about $4-6k depending on the complexity.  I haven't done any in-floor heating, though that seems somewhat labor intensive.  I would think you could get the plumbing rough-in for something about half of that ($2-3k).  So, unless your design is more complex than most, I'd think you should be in the $6-10k range.  Fixtures could add quite a bit to that depending on spec.

I'd also recommend 4" diameter main drains.  In MN, you cannot have more than 2 toilets discharing into a 3" drain... ran into that myself recently.

[ReadySetMillionaire]

Any chance this plumber meant $4,600 and accidentally added a 0?

[maxpower]

Thanks for the responses here!

Ha ha ha!!! It gets worse! He forgot to add in the rough in plumbing to the estimate (another 9000!). It's now over $55,000!!!

I have bid from another plumber/HVAC guy in the works (I'd like to get at LEAST one more beyond that). He seemed much more willing to listen to the kind of values we live by as a family and to design a system accordingly. The first company definitely built a Cadillac, but we, however, live my much more frugal energy consumption standards. Wish me luck!

[RichMoose]

Something that might be adding cost is that you have multiple systems in the same building so equipment costs are higher. Also, in my area newly installed wood stoves are costly because of the fire codes and ventilation requirements to maintain air quality.

 For $25,000, you should easily be able to have an in-floor hydronic heating system for the whole house, including plumbing for fixtures.

For forced air system (HE furnace and AC) and plumbing you should be all in for $15,000.

Your insulation standards, window performance, etc should factor into the size of system you need. Good HVAC contractors should be doing a Manual J calculation. For a new, well insulated home of your size, the effective output of your furnace should be no more than 55000 BTU, (or 60000 BTU furnace that's 92% efficient).