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Do A Lot Of People Use A Faucet Adapter To Fill Their Spas?


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Do you use the outside and cold water to fill your tub or inside with house water heater?  

28 members have voted

  1. 1. Do you use the outside and cold water to fill your tub or inside with house water heater?

    • I use the outside faucet and wait to heat up
    • I use the cheaper to heat inside faucet with adapter and can go in right away
    • Never thought of it, but will try this
    • Thought of it, but like to pay more for heating up the water and waiting is fun. lol
      0
    • I don't think it is cheaper to heat the water this way.
    • I have a direct connect from my house water heater to my tub
      0


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I was wondering since I never see posts about this. After my first initial fill, when I had to refill due to extreme bather load on this new toy and the likely leaching in the pipes from a brand new spa, I bought a water bed fill/drain kit from an aquarium store to fill my spa with the water from my much more efficient oil fired water heater in the house instead of 42 degree water from the outside hose spigot to not only save power costs, but so that I could go in the spa right after filling and not have to wait for the inefficient electric heaters to heat up the water to 100 degrees.

So how many people do this? If they do not why not?

EDIT:

Added a direct connect option to the poll. I think this would have fallen under the faucet adapter answer for the most part for power savings/quicker dip time after the change though, but now we have that option.

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I guess my response in none of the above. When I installed my tub in addition to running electrical service to the location I also ran hot and cold water and installed a frost free sillcock that provides either hot, cold or a mix. Google Moen HC400508PX. I have attached a short length of hose to the sillcock with an adapter and shower head (see Gaiam Energy Saving Showerhead)which we use to rinse off in the summer after returning from the beach a few blocks from our home (we still get sand in the trunks but don't wear those into the tub at night). I remove the showerhead, which restricts the flow, when filling the tub from the sillcock. It works great and is cheaper for us since our hot water is provided by a high efficiency gas boiler from our radiant heating system in the floors. Electricity is cheap in Seattle, but the gas heated hot water is cheaper, but saving time to get up to temp is the main reason I do it. I run out of hot water before the tub is filled but we are usually in the mid to upper eighties by the time the tub is full so it saves a lot of time in reaching our 102 target temp. I realize that this probably does not help you figure out how to fill your tub but may be helpful to someone in the planning stages.

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Thanks for the response. I added another answer to cover your method. I didn't even think of this but your hook up is for a multi-use reason that works off the same reason I use an adapter to fill mine now. I may end up doing what you did even though I am 40+ miles from a beach, to just have this option for similar reasons of having an outdoor shower hook up. It should be fairly easy since the boiler/boiler mate system in my house is a straight line on the same end of the house to the spa. I would love to hear arguments for letting the tub heater do the work of heating up the water if anyone feels this is a better choice. I just do not see it.

So feel free to choose the last new answer now.

Thanks for replying as I will be interested in how many people use the house water heater, and if I can help others who may have never thought of this before.

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I was wondering since I never see posts about this. After my first initial fill, when I had to refill due to extreme bather load on this new toy and the likely leaching in the pipes from a brand new spa, I bought a water bed fill/drain kit from an aquarium store to fill my spa with the water from my much more efficient oil fired water heater in the house instead of 42 degree water from the outside hose spigot to not only save power costs, but so that I could go in the spa right after filling and not have to wait for the inefficient electric heaters to heat up the water to 100 degrees.

So how many people do this? If they do not why not?

EDIT:

Added a direct connect option to the poll. I think this would have fallen under the faucet adapter answer for the most part for power savings/quicker dip time after the change though, but now we have that option.

A 360 gallon tub takes appx 180,000 BTU to raise the temp 60 degrees from 42 to 102. That's 53KW, and at $.10/KW, just over $5. Assuming your oil fired heater is 2x as efficient, you're saving about $2.55 per fill in heating costs. Evaporative loss / radiation loss while the top is off for fill and normal use is about $.45-$.55 per hour depending on wind and humidity conditions (and whether you are injecting cold air while using). And then there is the normal loss through radiation / convection / evaporation when your tub is sitting idle the 99% of the time it is not in use (you're looking at $.50/day + for even the best tubs out there). The short version is that the $$ to heat the tub on initial fill are only a small, small fraction of the total operating costs of the tub, unless you're refilling all the time (like weekly). This boils (pun intended) down to a convenience factor- whether or not you want to wait for the tub to heat after a refill. Because the $$ don't matter. It'll take you at least several refills to cover the costs of the aquarium kit alone (I know this- that's where the "reef" in reefreak comes from). And then you're dealing with a much more restricted flow rate off of your kitchen sink and the hassle of stringing pipes through your house than a 3/4" garden hose running full bore. Hope this helps.

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As my hot tub is heated via a heat exchanger system incorporated into my house hot water heater (natural gas), filling from the outside hose makes no difference in heating cost. Besides, my hot water heater only holds 30 gallons, so once depleted into a 400 gallon hot tub it's putting out cold water anyways.

FYI, electric heaters are nearly 100% efficient. Virtually all the energy put into them is output as heat. Gas heaters, a percentage of the energy goes up the flue.

Also, it's been my experience that the cost to heat with electricity is about equal to oil or propane (natural gas tends to be cheaper). Oil, LPG and NG though will heat much fasted than electricity.

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Potable water is scarce where I live. I fill my hot tub with rainwater collected from the roof of the house. I have all my down spouts joined into a collector that diverts the rainwater to a 1200 gallon cistern. When the cistern is full, the water overflows to a line that goes downhill to a county drainage ditch. I have a shallow well pump and a pressure tank that feeds a non-potable water system that I use for the hot tub, garden, washing cars and flushing toilets. The water in the cistern stays about 50 degrees year round. My hot tub heats the 50 degree water to 103 degrees in less than twelve hours. I use the dichlor/then bleach method for sanitizing the spa and refill it once a year.

Dave

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I agree 100% with reeffreak and doc.

Long ago I was curious about the cost to fill a tub and determined the total to be about $10 plus balancing chems, with our costs for water and utilities. The water cost included a sewer charge as well since that that charge is based on water demand unless you meter separately for water that does not go down the sewer, such as irrigation. I was considering a 400 gal tub and I since used $0.8 per KWH which is a little higher than our rates and came up with $4.06 to heat the water, right in line with reeffreak's determination of a little over $5 with rates @ $.10 KWH for a 400 gal tub. This assumes 100% efficiency but in reality the efficieny will be a little less because although electical heat is 100% efficient the will be some loss at the heater into the equipment bay.

For gas heat my boiler is a high efficiency condensing boiler that is supposed to be around 95% efficient but I will also lose heat in the water line that runs from my house to the sillcock, in the hose etc. If it was 100% eff icient with my price for natural gas the cost to heat would be $2.01. As I said it won't be near 100% efficient but I doubt that it willbe less that 50% which is what it would have to be at for about the same cost as electic heat at the tub.

Anyway the point is, I have the hot water near the tub for another reason but using it when I fill means that I can get up to temp quicker.

As a side note, the reason that I was curious about the cost to fill is I was always reading about how great the water feels after a fresh fill but I also read about how people seem to try to stretch out the time between fills. Thus I thought that maybe it was costly to fill a tub but my calculation indicated otherwise.

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As my hot tub is heated via a heat exchanger system incorporated into my house hot water heater (natural gas), filling from the outside hose makes no difference in heating cost. Besides, my hot water heater only holds 30 gallons, so once depleted into a 400 gallon hot tub it's putting out cold water anyways.

FYI, electric heaters are nearly 100% efficient. Virtually all the energy put into them is output as heat. Gas heaters, a percentage of the energy goes up the flue.

Also, it's been my experience that the cost to heat with electricity is about equal to oil or propane (natural gas tends to be cheaper). Oil, LPG and NG though will heat much fasted than electricity.

My boiler is 85% efficient (21 years old now, but that is excellent for it's age), but I have a Boilermate hot water tank that runs off an extra zone in the house. Basically if i start at 135 degrees in the Boilermate i end up with 98 degree water when my 450 gal. tub is full. When the boiler is running to heat the house anyway the cost difference to heat the water is pennies in my system. I figured roughly in my head as a guess that it would cost about $10.00 ($0.119/KWh rate I pay) to fill and heat from the outside tap, but then I have a stiff hose that must be drained and rolled up outside in the winter here and then have to wait 12+ hours for it to get up to temp. So I am saving a little, but can go in right away AND roll up a warm flexible hose in the warmth of of my house in the winter also. The downstairs bathroom window is only 4' away from the tubso I just stuff a towel in the window jam to fill the gap in the window and keep most of the hose inside where it stays warm and pliable to roll up afterwards.

BTW, I keep the cover on while filling it as it is around 10 degrees outside now where I live and I avoid being out in the cold like that. I also bought 3 Arctic Pure Silver Sentinel micro disposable filters for $65.00 total to use in the winter for the same reason I like heating from the hot water tank. Last thing I want to do is be out there spraying a hose with 42 degree water when it is 10 degrees out there weekly to spray down the filter, and then have that water freeze up in the yard.

I guess if it is always fairly warm outside and above freezing it doesn't matter as much, but I hate being out in the winter and hate it more playing with 42 degree water when it is so cold outside even more.

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Most people have a standerd hot water system, not like yours. It don't take long to drain your 40-50 gallon hot water tank. And because of impatience I usualy use cold or a combination, mostly cold cause the tub can be full and heating before the hot water heater recovers from the first dump.

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Most people have a standerd hot water system, not like yours. It don't take long to drain your 40-50 gallon hot water tank. And because of impatience I usualy use cold or a combination, mostly cold cause the tub can be full and heating before the hot water heater recovers from the first dump.

My heater recovers heat as it is being drawn because it is oil fired compared to the electric heater in my parents house when i was growing up. I never had natural gas, but i always assumed those heaters recovered quickly as well. I think my Boilermate tank is only about 60 gallons so it is no where near the size of my 450 gal spa. But I did turn the temp on it up to 135 degrees so it would start higher and as the temp of the heated water drops it would average close to 100 degrees. Normally I keep the water heater at 125 degrees. I stopped it once for 5 minutes as well.

If you have a boiler you should check out those Boilermates. When I got it, I started using at least one less tankful of oil compared to the tankless that came with the house when new. It works with a gas fired boiler as well and comes with a lifetime warranty to the original purchaser. After 21 years mine had a slight leak, and they replaced the whole thing free (except the labor).

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I really don't see any real worthwhile cost savings in using hot water to fill the tub. At best, you are saving maybe a couple of dollars and in my case, I wouldn't have hot water for my household needs after filling the spa. I'll happily spend the buck or two it might take to heat the water in the tub and I'll happily fill my tub in the morning and then use it that same night. My spa isn't such a necessity that I can't live without it for a few hours while it's heating up especially since that only happens a couple times per year. I'll save my hot water for showers, dishes, dirty clothes, and other household needs. My tub will make it's own hot water, and my shower won't. I also don't agree with the selection that says "cheaper to heat inside faucet". If you want me to believe that, you'll have to show me some facts and not just express a personal opinion because I don't think it's any cheaper. In my case, I'm almost positive it isn't since my home is all electric.

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I really don't see any real worthwhile cost savings in using hot water to fill the tub. At best, you are saving maybe a couple of dollars and in my case, I wouldn't have hot water for my household needs after filling the spa. I'll happily spend the buck or two it might take to heat the water in the tub and I'll happily fill my tub in the morning and then use it that same night. My spa isn't such a necessity that I can't live without it for a few hours while it's heating up especially since that only happens a couple times per year. I'll save my hot water for showers, dishes, dirty clothes, and other household needs. My tub will make it's own hot water, and my shower won't. I also don't agree with the selection that says "cheaper to heat inside faucet". If you want me to believe that, you'll have to show me some facts and not just express a personal opinion because I don't think it's any cheaper. In my case, I'm almost positive it isn't since my home is all electric.

It wouldn't be less expensive naturally if your inside water heater is electric also. It likely wouldn't provide savings if you have a tankless system either because the tankless is typically only about 3.5 gallons and the boiler would run constantly and not produce water hot enough. I know this because my house came with only a tankless and it took over an hour to fill the bath tub upstairs. That was part of the reason I got the Boilermate. SInce I got it 21 years ago it saves on average at least 1 275 gal. tank of oil per year, and likely more now that I have 7 people living in the house with two teenagers who shower sometimes twice a day.

When I checked the temp in the tank after filling the tub about 2/3 full it read 86 degrees in the tank from the original 135 degrees So it wasn't like I had only cold water in the house, and the total time to fill was less than 1 hour so filling it does not create any long term loss of hot water in the house either. My system will be back at full temp in the tank within 5-10 minutes. If it saves only $5-10.00 per fill and you fill 4x per year that is $20-40.00 saved AND you get to use it right away also. For those living in very cold climate this is also more beneficial because you have less issues with hoses freezing etc, that many in warmer climates likely do not understand or have to even think about. I have only had my spa for 1.5 months now but had to refill it 3x already including the initial fill. I dumped the first fill when I changed from Bromine to Chlorine after 3 weeks, and then again after a party where 3-5 people were in the tub constantly for 6 hours straight. :o So even if only $5.00 is saved, that would be $15.00 saved in 1.5 months fort me.

So save money (amount debatable depending on water heating system in the house and electric rates), can use the hot tub right away, is more convenient if you live in a cold winter climate with much easier hose stowing etc., it seems to be a good thing all around.

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I live in a cold climate (Ohio), and like I said, I can wait the few hours it takes to heat the tub. As for hose freezing, it's never been a problem. I'll have maybe 1 refill during the winter at best and my tub is just a couple feet from the faucet. I use a cut off piece of hose that's no more than 6 feet long. A month and a half? I've had tubs for 25-30 years. I hope you enjoy using your's as long.

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When I checked the temp in the tank after filling the tub about 2/3 full it read 86 degrees in the tank from the original 135 degrees So it wasn't like I had only cold water in the house, and the total time to fill was less than 1 hour so filling it does not create any long term loss of hot water in the house either. My system will be back at full temp in the tank within 5-10 minutes. If it saves only $5-10.00 per fill and you fill 4x per year that is $20-40.00 saved AND you get to use it right away also. For those living in very cold climate this is also more beneficial because you have less issues with hoses freezing etc, that many in warmer climates likely do not understand or have to even think about. I have only had my spa for 1.5 months now but had to refill it 3x already including the initial fill. I dumped the first fill when I changed from Bromine to Chlorine after 3 weeks, and then again after a party where 3-5 people were in the tub constantly for 6 hours straight. :o So even if only $5.00 is saved, that would be $15.00 saved in 1.5 months fort me.

So save money (amount debatable depending on water heating system in the house and electric rates), can use the hot tub right away, is more convenient if you live in a cold winter climate with much easier hose stowing etc., it seems to be a good thing all around.

Heating oil has about 140,000 BTU per gallon. When you calculate loss from your boiler (.15) and loss from the pipes thru delivery (.15 est- copper in your house is prob not insulated, nor is that aquarium hose), you're going to net about 100,000 BTU/ gallon. I'm going to wag your tub at 200,000 BTU (the exact amount doesn't really matter- this is a comparison), and at $2.50/gal for oil, you're talking about $5 (assuming that 21 yr old furnace is really still .85). This same amount of electricity per your $.119 rates (@ a conservative 95% eff) is $7.31. So the delta is < $2.50, which is right in line with my first response. Your $$ savings estimates of $5-10 are somewhere between 2-4x high. It's best to figure out your water chemistry so you aren't refilling every 2 weeks. That will save you far more $$ (and time).

The only economics that I've seen that work in heating a tub for less money is direct solar gain. If you have a dark shell tub, and if you live in a sunny climate, The sun alone will take your tub up to temp in the summer.

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Calculating how much it costs to get the water up to temp using the hot tubs (electric) heater is very simple...

Time x Heater KW rating x Cost/kWh

For example, my tub uses a 6 KW heater, and takes about 10 hours to get from 52 deg (straight from the cold faucet) to 102 deg. Which means it uses 60 kWh (10 x 6) of electric to get up to temp. Here in NY a kWh is $0.15, times 60 = $9. Another way to look at it is the heater costs $0.90 per hour to run (or 6 x $0.15).

Then there's the cost of the water of course.

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When I checked the temp in the tank after filling the tub about 2/3 full it read 86 degrees in the tank from the original 135 degrees So it wasn't like I had only cold water in the house, and the total time to fill was less than 1 hour so filling it does not create any long term loss of hot water in the house either. My system will be back at full temp in the tank within 5-10 minutes. If it saves only $5-10.00 per fill and you fill 4x per year that is $20-40.00 saved AND you get to use it right away also. For those living in very cold climate this is also more beneficial because you have less issues with hoses freezing etc, that many in warmer climates likely do not understand or have to even think about. I have only had my spa for 1.5 months now but had to refill it 3x already including the initial fill. I dumped the first fill when I changed from Bromine to Chlorine after 3 weeks, and then again after a party where 3-5 people were in the tub constantly for 6 hours straight. :o So even if only $5.00 is saved, that would be $15.00 saved in 1.5 months fort me.

So save money (amount debatable depending on water heating system in the house and electric rates), can use the hot tub right away, is more convenient if you live in a cold winter climate with much easier hose stowing etc., it seems to be a good thing all around.

Heating oil has about 140,000 BTU per gallon. When you calculate loss from your boiler (.15) and loss from the pipes thru delivery (.15 est- copper in your house is prob not insulated, nor is that aquarium hose), you're going to net about 100,000 BTU/ gallon. I'm going to wag your tub at 200,000 BTU (the exact amount doesn't really matter- this is a comparison), and at $2.50/gal for oil, you're talking about $5 (assuming that 21 yr old furnace is really still .85). This same amount of electricity per your $.119 rates (@ a conservative 95% eff) is $7.31. So the delta is < $2.50, which is right in line with my first response. Your $ savings estimates of $5-10 are somewhere between 2-4x high. It's best to figure out your water chemistry so you aren't refilling every 2 weeks. That will save you far more $ (and time).

The only economics that I've seen that work in heating a tub for less money is direct solar gain. If you have a dark shell tub, and if you live in a sunny climate, The sun alone will take your tub up to temp in the summer.

If it takes 12 hours to heat up the water from 42 degree to 100 degrees with the internal electric heater in the spa, that means the pump has to be going for 12 hours also to move the water over the heater. My tub doesn't have a separate circulator pump and my heater is 4,000 Watts. So that is an additional power cost during the heat up time at least with my spa.

That 85% efficiency rating is from last month when I had my boiler cleaned and tuned so that IS the current efficiency. My hot water pipes for the exposed pipes are insulated as well. I assume the pipes in the walls are insulated by the wall insulation also.

As far as keeping the chemistry adjusted I know this. I got the new spa recently so it is a learning curve as you may remember when you first got yours. I started off with a Bromine system with the first fill up. It could not keep a residual of bromine and maybe it was because of the new pipes leaching, but the water could not get crystal clear so I changed over to the Dichlor/bleach system I got from this forum. It has gotten VERY heavy use in the first 1.5 months and I had to refill again after my birthday party where there was on average 3-5 people in it for 6 hours straight. This is after having on average on average 2 people for 2 hours/day 5 days per week after the initial refill. So that is why I needed a second refill after the initial one. I screwed up as well and put over double the Dichlor shock amount in the night before the party as well.It was at about 30ppm of FC, so I added Hydrogen Peroxide to lower it to 10ppm so I could use it for the party.

This forum and all of you have been great for helping me learn about the water chemistry and diagnosing the issues and of course that great Dichlor/bleach method as well. So I thank all of you for all the knowledge I have been getting reading this forum. B)

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Calculating how much it costs to get the water up to temp using the hot tubs (electric) heater is very simple...

Time x Heater KW rating x Cost/kWh

For example, my tub uses a 6 KW heater, and takes about 10 hours to get from 52 deg (straight from the cold faucet) to 102 deg. Which means it uses 60 kWh (10 x 6) of electric to get up to temp. Here in NY a kWh is $0.15, times 60 = $9. Another way to look at it is the heater costs $0.90 per hour to run (or 6 x $0.15).

Then there's the cost of the water of course.

And the power cost to run the pump for 10 hours in your case to move the water through the heater too.

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Calculating how much it costs to get the water up to temp using the hot tubs (electric) heater is very simple...

Time x Heater KW rating x Cost/kWh

For example, my tub uses a 6 KW heater, and takes about 10 hours to get from 52 deg (straight from the cold faucet) to 102 deg. Which means it uses 60 kWh (10 x 6) of electric to get up to temp. Here in NY a kWh is $0.15, times 60 = $9. Another way to look at it is the heater costs $0.90 per hour to run (or 6 x $0.15).

Then there's the cost of the water of course.

And the power cost to run the pump for 10 hours in your case to move the water through the heater too.

Your point would be valid IF I had to run the main pump(s) to heat the water, however in my case the 24/7 circ pump pushes water through the heater, whether heat is needed or not, i.e. the main pump(s) play no part in heating the water. The additional cost is therefore zero.

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