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reveriereptile 03-03-2012 01:26 PM

How big should a mechanical/utility room be?
I'm trying to figure out how big to design the mechanical/utility room. It will be for a 1.5 story house with all water usage one the same side of the house as the utility room.

The washer and dryer won't be in this room. I don't know of everything that goes in the room but I know I need room for an electric water heater and the circuit panel box. If the circuit panel can't go in there I don't mind putting it in the hallway. We will probably go with hydronic radiant floor heating. I would like a drain in this room if it does need one.

How big should I make the room without making it to small and within the code requirements? I don't want to waste a bunch of space in the utility room that could instead be used for the bathroom. Can the door for the room be through the bathroom or does it need to be through the hallway?

woodworkbykirk 03-03-2012 02:36 PM

the mechancial room has to be big enough for all the furnace. hot water tank and any thing else to fit inside plus enough room for someone to service all of them.

your best bet is to lay it out on the floor using masking tape so you can better visualize how the space is being used

TarheelTerp 03-03-2012 05:00 PM

Graph paper... it's a GoodThing

SPS-1 03-03-2012 07:30 PM


Originally Posted by woodworkbykirk (Post 869334)
the mechancial room has to be big enough for all the furnace. hot water tank and any thing else to fit inside plus enough room for someone to service all of them.

having enough room to service the unit is an important consideration that is sometimes neglected. Don't forget the lighting either.

Just one more thing... the doorway should be big enough (and positioned with respect to the rest of the house) to get a hot water heater or furnace through. You may need to replace it one day.

Missouri Bound 03-03-2012 08:08 PM

Take a look at some of the examples for hydronic heating. Depending on the system it has several controls and valves and pumps and take up quite a bit of wall space. Keep that in miind when designing the room.:thumbsup:

md2lgyk 03-05-2012 08:58 AM

My wife and I designed and built our own log home, and we didn't want to waste a lot of space on utilities either. We have a tankless gas water heater - it's in the attic. The well pressure tank, backup furnace and air handler are in the crawl space (it was built 4 feet high for just that purpose). Fact is, we don't even have a utility room as such. The only thing that's not tucked away somewhere is the water softener - it's in a corner of the laundry room.

yogi_bear_79 03-05-2012 09:50 AM

Find the space requirements for your boiler (hydronic heating). The circuit panel can go in there, as long as you meet the code requirements for clearances around it. Missouri Bound mentioned it already, the hydronic heating pumps, zone controls, manifolds and piping all take up considerable space. You should really consult with your HVAC contractor to ensure there are no surprises when fitting that equipment. I have recently built a 40 x 40 building, and a house, both with hydronic heat. My utility rooms are quite small, yet well organized.

Also you will have to account for the air intake of the boiler, if a room is too small either a vent needs installed in the door, or fresh air ducted from another room/space.

What about hot/cold domestic water? Are you doing a home run PEX system? If so you will need wall space for the manifold.

If you are doing hydronic heat, look into an indirect water heater versus the electric tank you are considering.

reveriereptile 03-05-2012 11:43 AM

Thanks for all the replies and tips.

I know we will have to have a well for our water since the location is out in the country. I would like to have the hydronic system closed. I don't want our shower/drinking water running through the floor. As far as whether we are going to use a boiler or water heater to run it I'm not sure what to go with yet. The house will be around 1670 sq.ft. but not all of that will need heating. I'm assuming the tubing will need to be placed close together in one of the zones due to having a lot of windows in that area. We will have probably 3-4 heat zones. Should we use a boiler or a water heater for our house to run the radiant system?

We will have a pretty much straight staircase (11' long with a small corner at the end) that will have an empty space under it. I'm not sure if the electrical stuff could go under it or not. The staircase is on the opposite side of the house that all our water usage is on. I'd like to keep the water heater/boiler on that side with the other water appliances.

The spot that I'm thinking about putting a utility room in is around a 4' or 5'x11' area. Does that seem big enough or should it be bigger? I could move my kitchen and loft down some to make more room.

yogi_bear_79 03-05-2012 12:54 PM


I would like to have the hydronic system closed. I don't want our shower/drinking water running through the floor.
This is a standard setup. You would not mix the two.


Should we use a boiler or a water heater for our house to run the radiant system?
What type of fuel do you have available? Oil, natural Gas, Wood, Coal, Electric, etc.

A lot of this depends on your location, and house construction type. Is this on slab, on a full basement or a crawlspace? It sounds as if you are designing this yourself. Here are some things to ponder. Can you centralize your domestic hot water to the destinations that need it (i.e. kitchen, bath, laundry). This will greatly improve the overall system performance. Same with the hydronic heating tubes. Zones are broken down into loops, in most cases 1/2" PEX should be limited to 300' or less per loop. How many loops per zone depends on floor plan and zone size. If you can centralize your hydronic source, it will most likely aid greatly in your design, cost and performance.

The electrical under the stairs.
Can wires be easily routed to this location?
Does it meet all other code requirements, as far as working space around the panel?

The size of the utility closet you describe "might" work, it might not. You really need to break down what is going in the space. The type of fuel you intend to heat with will help narrow down "rough" sizing of the boiler. In my case I fit a 400 Amp service panel, Oil Boiler, PEX domestic distribution manifold, and a two zone (in floor) hydronic system in that space. However, my space has two doors, so as to access the boiler from either side. Otherwise maintenance on the boiler and hydronic could be quite cumbersome.

In my house, the utility room wasn't thought out as well. I ended up moving my domestic cold distribution to another location. I also added a recirculation loop to my domestic hot because my domestic hot source was as far away as possible from the master bath! L I did however fit my boiler, hot water tank, two oil tanks, electric and my hydronic pumps in there, with remote manifolds.

Personally, I wouldn't attempt to heat the house with a hot water tank. I would use a boiler, and incorporate an indirect hot water heater.

reveriereptile 03-05-2012 01:37 PM

Thanks again for the reply.

We are designing the house but have a friend that is an architect that will be drafting the actual floor plan and certifying it. Pretty much we need to sort of have what we want to give to him and then go over it with him and he can tell us what needs to be changed. We would be using electric since we only have the choice of it or propane. The propane is more expensive around here.

The downstairs of the house is around 1040sq.ft. on a slab. The upstairs is around 617sq.ft. It is a prow front house. We already went over all the pros and cons of this type of house but the pros outweighed the cons. The utility room I was going to have between the kitchen and the bathroom with a bathroom upstairs above them.

Here is sort of what the floor plan looks like. I was messing around in Sweet Home 3D to get more of a visual of the plan and to help move stuff around easier than on paper. If anyone has any tips or opinions on the plan layout feel free to tell me. This definitely isn't the final plan and does have changes that needs to be made. It is the closest to what we want.

yogi_bear_79 03-05-2012 02:58 PM

I like the Prow front idea! I am sure you heard all about the windows and the high ceiling. But if you are informed, I say go for it! My great room brought me the same flak.

My opinion, that bathroom downstairs is huge! What is that, 10 x 11? I would reduce that, slide everything back and make the kitchen bigger. Unless that is also the laundry room?

I like that the utility room is central to all the water needs in the house. On my comment about the bathroom. Maybe you could make the bathroom smaller, take the remaining space and split the utility into a two section room, laundry in the front utility in the rear (if it all fits mechanical wise)

I would think the master bedroom double doors should open in as well

Do you have a plan for a mud room or closets or something at the entrance at the end of the long hallway? I assume this is your main entrance?

I see they make electric boilers. I think it would be worth a look at least. I know people have used water heaters for hydronic, but I don't believe it is common practice in a home, more so for smaller areas. You could do an electric boiler, indirect hot water heater, and all of your hydronic equipment and domestic sourcing from the utility closet. Based on your layout I wouldn't use the space under the stairs for electrical. I would incorporate built-in storage in the living room area or into the bedroom closet. I think I would get the electrical into the utility as well.

In order to answer these things you really need to focus on what needs to be in there. I see at least two zones for the hydronic, upstairs and downstairs. You could break it down further if you really have a need to have different temperatures in different areas of the first floor.

The PEX in the slab is great! You will love the performance. Give some thought in advance on how you want to run the PEX for the second floor. There are several methods both above and below the sub floor.

You previously asked about putting the door to the utility room in the bathroom. I can't see why technically you couldn’t, but aesthetically speaking I wouldn’t do it.

As far as code for the utility room, it is going to be based on what is in there. And the subsequent clearances required for these items.

Are you building this yourself or part of it , or contracting everything?

Blondesense 03-05-2012 08:15 PM


Originally Posted by yogi_bear_79 (Post 871145)
Do you have a plan for a mud room or closets or something at the entrance at the end of the long hallway? I assume this is your main entrance?

Yeah, don't forget storage and closets. Coat closet, linen closet, general storage, etc. Figure out what you think you might need and double it. BTDT.

For instance if that hallway does not have to be a main exit, it looks sorta wasted. Assuming the drawing is situated as north is up, you could slide the bathroom door west and turn the end of the hallway into a closet for one bedroom. Hallways eat up square footage.

Beyond that it is hard to make suggestions without knowing how the house will be situated. For instance, where will your main entrance be? Where will you park? Is traffic noise an issue, and if so, from what direction? Etc. etc.

md2lgyk 03-06-2012 09:09 AM

Another space saver I forgot to mention is a spiral staircase. My wife saw one somewhere and on the spot decided that's what she wanted. It came in kit form and wasn't difficult to install.

md2lgyk 03-06-2012 09:11 AM

What's the scale on your drawing? I think both of your bathrooms are seriously too big.

concretemasonry 03-06-2012 11:06 AM

I think the utility room is a poor shape because if you have a boiler/furnace in there and a water heater in there one wall will inaccessible and any electric panel must have enough space in from of it.

If either the water heater or furncae has to be removed and it is in the back, the other will have to be removed to get the back unit out.

Dimensions would help, but it looks like the room is a little wider than the door, which make repairs/removal/servicing difficult with a big shoe horn.


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