sauna heater recommendations

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Pursuivant
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Re: sauna heater recommendations

Post by Pursuivant » Thu Oct 29, 2009 7:21 pm

BTW now that you're getting there, remember I am still looking for a "Warning - Electric Sauna - do not throw water on the rocks" placque :lol:
"By the pricking of my thumbs,
Something wicked this way comes."

Re: sauna heater recommendations

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Ravvy
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Re: sauna heater recommendations

Post by Ravvy » Fri Oct 30, 2009 5:05 pm

Great feedback, thanks! :D
I'm wondering about these ventilation recommendations (mentioned earlier and also in the kit specs) when using an electric heater. In Finland I never saw vents in the walls as recommended by the kit manufacturers over here in their websites. Don't these vents just allow escaping heat to warm up adjoining rooms (like the "cool down" room, for example)? The inside electric saunas I saw in Finland had a very small electric exhaust vent in the ceiling which could be turned off & on, and vented to the outside (either into the chimney flue or directly outside). So what is the thinking with permanent wall vents in the heat-up room?
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Upphew
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Re: sauna heater recommendations

Post by Upphew » Fri Oct 30, 2009 5:49 pm

Ravvy wrote:Great feedback, thanks! :D
I'm wondering about these ventilation recommendations (mentioned earlier and also in the kit specs) when using an electric heater. In Finland I never saw vents in the walls as recommended by the kit manufacturers over here in their websites. Don't these vents just allow escaping heat to warm up adjoining rooms (like the "cool down" room, for example)? The inside electric saunas I saw in Finland had a very small electric exhaust vent in the ceiling which could be turned off & on, and vented to the outside (either into the chimney flue or directly outside). So what is the thinking with permanent wall vents in the heat-up room?

You are not supposed to vent the air from the sauna to the other rooms, mainly because of the moisture, but good ventilation is otherwise necessary.
http://www.suomela.fi/ilmanvaihto-tekee-saunan.aspx
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Ravvy
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Re: sauna heater recommendations

Post by Ravvy » Fri Oct 30, 2009 8:48 pm

Here specifically is what I don't understand (see attached link). The text says the vents are to an ajoining room in the house. I've never seen that done anywhere and would not do it myself, yet this designer/ manufacturer recommends them.
http://www.finlandiasauna.com/sauna-ventilation.html
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Pursuivant
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Re: sauna heater recommendations

Post by Pursuivant » Fri Oct 30, 2009 9:09 pm

Yes well the *in* vent at the floor level can and maybbe should be from an adjoining room, but the "out" or top vent ought to go outside...
"By the pricking of my thumbs,
Something wicked this way comes."


suomitranslation
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Re: sauna heater recommendations

Post by suomitranslation » Sun Dec 20, 2009 6:12 am

The grill is because getting burned with hot metal feels oh so much better than getting burned by hot rocks. :ochesey:

I emailed IKI a few days ago about importing one of their electric units. It would take some modifications, but they seemed amenable to discussing the possibility.

Finlandia is quite customer friendly (the CEO called in response to some difficult questions I emailed them). I'm not so sure about the western red cedar (tuija) wood they specialize in. There are so many horrible cedar saunas in the US. For the sauna I'm putting in my home this coming year I'm thinking of using Superior Saunas as my source for walls and benches in good light woods and buying an Ainavalmis/Hetivalmis/Saunatonttu heat storing electric stove from whomever will sell it to me cheapest. Unless the thing with IKI works out. That would be sweet, but I wouldn't have a warranty...

Maybe an electric Hariva and a wood burning IKI!


davin
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Re: sauna heater recommendations

Post by davin » Sun Dec 20, 2009 11:24 pm

Also consider what electrical power you have in your house. Most stoves are 3 phase (415volts).

I wanted to install one in the uk, but as the uk runs on 240 (domestic) I would have have melted half the town.
There are 240 models, but they are simply not powerful enough - might as well just sit in front of a boiling kettle.

just a thought


suomitranslation
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Re: sauna heater recommendations

Post by suomitranslation » Tue Dec 22, 2009 7:08 am

I'm not an electrical expert, but does having such a high voltage necessarily matter in terms of the power output of the unit? In Finland the standard stoves are around 6-9 kilowatts, depending on the application (12 or more for commercial spas). The units sold in the US for 1-phase 240 volt power (instead of 3-phase 400 volts) are also rated in the same kilowatt range. Since watts are volts times amperes, doesn't this mean that the 240v stoves produce exactly the same power at the same rate (1 watt=1 joule per second), but just using a higher amperage?

So a 7.5 Kw heater on a 240 v line will need to draw something like 30 amps instead of the 18 it would draw at 400 volts. There is a little bit of funky math that goes into getting the real values (the amperage is actually lower I think). A normal clothes dryer runs on 30 amp fuses and homes generally have 100 amp service (up to 200?). In other words, there should be no problem getting just as much power to a sauna stove in the US/UK as in Finland.


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onkko
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Re: sauna heater recommendations

Post by onkko » Tue Dec 22, 2009 7:26 am

CBA to count but 31A need 6mm2 wire and 19A needs 2,5mm2 wire.
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Tiwaz
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Re: sauna heater recommendations

Post by Tiwaz » Tue Dec 22, 2009 9:48 am

There is one little difference between 1 phase and 3 phase besides voltages and outputs.

When you have 1 phase electricity, you might have 3 wires. Phase, null and ground.

3 phase has 5. Phase 1, phase 2, phase 3, null and ground.

I am digging my old memories from this field here below so do not take it as absolute truth but good approximation...

3 phase has itself phased so that at any given time there is as good output of power as possible. This because current or voltage changes to opposite at certain frequency in AC. This also means that there are 2 points when output is minimal.

Here is picture from wikipedia to explain. Picture is of 3 phase electricity, for 1 phase you only have one of the phases (red, green or blue not 2 or all 3).

Image

As you can see, each phase goes to 0 regularly. This is when power output also is minimal. 3 phase electricity solves this by having 3 wires in different phase so all 3 are never at 0 at same time.


What is the benefit/difference? Well, sauna stove draws power from wires at rather constant rate.
If we have only one phase, this one phase has to draw enough current to provide enough power for to stove to reach 6-9kW output.

That means actual amperage would be higher than assumed, because peak times would have to compensate for low points, which does not happen with 3 phase power.


suomitranslation
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Re: sauna heater recommendations

Post by suomitranslation » Tue Dec 22, 2009 9:57 am

But you get the same power in the same time, right? Just pulling more amps to do it because of the lower voltage/greater frequency of 0 points using single phase.


Tiwaz
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Re: sauna heater recommendations

Post by Tiwaz » Tue Dec 22, 2009 10:30 am

suomitranslation wrote:But you get the same power in the same time, right? Just pulling more amps to do it because of the lower voltage/greater frequency of 0 points using single phase.


Yes, you get same power. But amps goes way up.

So you might end up burning fuses or having your wiring heating up inside the walls trying to provide enough amps to your stove.


maxxfi
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Re: sauna heater recommendations

Post by maxxfi » Tue Dec 22, 2009 11:40 pm

Tiwaz wrote:What is the benefit/difference? Well, sauna stove draws power from wires at rather constant rate.
If we have only one phase, this one phase has to draw enough current to provide enough power for to stove to reach 6-9kW output.

I don't want to go into the gory technical details, but the main advantage is not that sauna draws power at constant rate,
but rather that the load gets distributed evenly on the three phases, and that because the currents in the phase wires
balance out each other there is actually no need to have a neutral wire.
In short, for a given electrical power, you need less copper wire.
Maxxfi


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Ravvy
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Re: sauna heater recommendations

Post by Ravvy » Wed Dec 23, 2009 4:30 pm

Since this thread has been reawakened, I'll take the opportunity to update you. I'm meeting this afternoon with a construction company (same group that remodeled & built an addition to our house several years ago) to see their bid/ cost estimate for the project. I had to rethink and scale-down this project to a much smaller size ($$). Right now we are planning to convert an existing bathroom closet into a small 1-2 person sauna. The heater of choice will probably be either a Harvia Compact or a Harvia Delta (fits into a corner), depending upon which fits better into the available space. The Compact is available in the USA but the Delta would have to be a special order, so availability might play an important role in the choice.
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LucyLove
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Re: sauna heater recommendations

Post by LucyLove » Mon Jan 11, 2010 6:36 pm

Hi!
I'm an italian girl, I'm really mad about Finnish saunas since I've moved to Finland two years ago for an Erasmus programme.. when I came back home I found this famous and well-known company ( http://www.finlandphilosophy.com/defaulteng.asp )and now in a few days me and my husband will realize a dream: a (little but wonderful) sauna at home!!! :D :D :D


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