What do u think? Hot water -- is 104 F not hot enough?

Dear Fellow Hosts,

I need your help, please. I have two apartments that I book via Airbnb. I have 90+% of 5 star stays. Most of my guests stay at least a week, and I prefer booking longer stays of 2+plus weeks. Due to the low season I decided to make an exception and allowed shorter bookings.
My current guests, a lovely couple from Europe, contacted me on Memorial Day about not having hot enough water; I was in a panic as I never had water temperature problems and drove quickly to the apartment whereupon I turned on the shower and was ecstatic when hot water came out. I asked the guests to test the water temperature and they insisted that it was not hot enough. On Tuesday morning I contacted a well known company to come to the apartment to check my water heater, etc. I met the two technicians at the apartment and they reported that there was nothing wrong with the water heater and tested the water temperature and confirmed that it was 104-105F which is standard for residential units and that there was no reason to replace the water heater; I paid $75 for the visit and reported the company’s feedback to the guests, explaining that even if I could make it hotter, I would be concerned to do so because I have lots of young children as guests. As a sign of good faith I reimbursed them for one night of their 4-night stay.
I’m really concerned about an unwarranted bad review – please see exchange of messages below and let me know your thoughts, please. Should I offer to reimburse the entire stay to avoid a bad review?Thank you.

Good morning X and Y,
Thank you for your message. I’m so sorry I was unable to satisfy you in terms of the water temperature. I’ve had guests from all over the world staying at the apartment and I never had any complaints about the temperature of the water; my husband and I have recently stayed at the apartment and showered several times and were happy with the water temperature.
Naturally, I want to satisfy my guests and I paid a company $75 to come check the equipment yesterday and the technicians found no problem.
As I mentioned, I will reimburse you for one night as a sign of good faith and to show you I truly care about the quality of your stay.
Have a wonderful day!

Today at 8:20 AM

Good evening !

Thank you for your follow up but we still find it a pity to have such almost cold water for our shower and bath. It just can’t be at 105 °F because we feel it directly colder than our body temperature. Maybe there is something with the thermostat. We’ve been renting Airbnb’s all over the States for seven years now and it’s the very first time we hear such thing about the risk for burnings. We’ve never experienced that water problem in other appartments nor in the hotels in which we stayed before coming to your place. Parents are aware enough to avoid their children to get burnt. Your place has everything we need and is very comfortable except for that water problem. We needed to make water boil several times to have an appropriate temperature.
Thank you for the tip for our boarding passes. We’ll do so. We’ll leave the apartment at about 9 o’clock on Thursday. It was a pleasure to meet you!

Kind regards,

In our area, and by code, water should be heated to 120º. If your water can’t get that warm, the inspectors deny your Certificate of Occupancy.


Your water heater should be 120 to 140 degrees. I turn mine up some in the winter due to some pipes going outside and then back into the house for the guest room. When I had a complaint last winter I turned it up myself I don’t have to call a plumber.


I agree. Any cooler and bacteria can lurk.


@KKC, @anon67190644, my mistake, the temperature is 140F and not 104F!

I went on the internet and this is what I found:

… Ideal Maximum Temperature Is… So what’s the ideal temperature then? The Consumer Product Safety Commission (CPSC) pins the ideal balance between safety and comfort at a setting of 120 °F (49 °C).


If it is 140 degrees F I would not raise the temperature. You run the risk of injury and it is more expensive to operate.

I think you’ll be caught between a rock and a hard place. Your temp does seem quite low - It’s actually within the prime range for the bacteria that causes Legionnaires disease to grow (anything less than 120).

OSHA guidelines suggest a minimum of 122 degrees at the tap, with the water heater set to 140.

However, child safety advocates say 140 is far too high and recommend 120, which still puts you in danger of LDB growth. I might split the difference and set it at 125 or 130 to kill the bacteria while not presenting too much of a burn risk to children.

One nights’ refund is plenty. As hosts we should try to address guests’ issues, but I think refunding should only happen when it impacted their stay in a major way (like there was NO hot water)


@Allison_H; @Brandt and everyone else, thank you for your guidance. I think I will replace my Titan heater to be on the safe side.

I think you swapped two of the digits.

Your note to them was excellent, I thought it was sincere and reasonable.
Speaking of water being too hot, in my condo complex we have boilers and I cannot control the temp. If I turn on only the hot tap, it is a scalding temp. My parents often stay in my condo while visiting, and my dad constantly complains to me that the hot water is too hot and he worries about my guests scalding themselves (nobody has. But my dad has advanced Parkinson’s and is elderly, so he is a bit more prone to accidentally putting his hands in too hot of water…all my guests tend to be younger and have more awareness of the temp). So if that ever comes up again, you could also mention that it’s a worry for children as well as seniors.
I sorta think the people are nit-picking. You clearly went out of your way to address the perceived issue, got a professional’s opinion, and were kind enough to refund a day of the stay. I assume they got at least 25% off their stay from that, and that is adequate. I think you have to chalk it up to the fact that you cannot please everyone, 100% of the time. If they leave a poor review, you can reply with the steps you took to respond- I’m sure prospective guests will be impressed with your level of effort and responsibility in a unexpected situation. I am after I read your post!


Firstly I am utterly amazed anyone from Europe could relate to Farenheit at all! Even in Britain, it is only retirement age people who use Farenheit.
The standard temperature of Thermostatic Mixing Valves in the UK is between 42 and 48 Cenigrade, which I calculated as 107.6 to 118.4 Farenheit. Therefore your water temperature is pretty low.
Personally I find hotter shower water drying on the skin, however there should be a choice of shower temperature. Some like it hot!

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BTW there’s a difference between the temperature the boiler should operate at, and the temperature coming out of the tap!

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My pal the contractor has an on-demand water heater. This nifty little appliance heats water as needed. For bathing it’s 110F. For dishwasing it’s 140F.

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In the UK most normal houses have gas combination boilers for central heating and instant hot water. Showers are separately regulated by thermostatic valves. It’s a good budget system.
In Germany etc. there are more mains pressure hot water systems which do give a better flow consistency and avoid temperature/flow fluctuations when taps are turned on.

If you look at the chart below, 120 degrees is the highest one should set the boiler at at if you have children or elderly users of the shower:

Boiler and tap/shower temperature will be different (boiler higher).

Personally I would have just turned it up to 120 for the remainder of their stay then re-adjusted it to the usual temperature after their departure.

We keep our hot water heater at 120.


104F or 40C is barely above body temperature. i can imagine if you are in the tropics then that is fine, plenty of people just shower using “cold” water from the tap or pour it over themselves. But some people like a proper hot shower so it probably should be at a minimum of 120F or 55C which is the temperature they set it in hotels so people don’t accidentally burn themselves. Even though I lowered my temperature to 65C or 150F my guests complain it takes too long to adjust to just right as it is too hot!

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I agree with your guests. 104-105 is not hot water that I am expecting.

This past year we put in both a new boiler and a new bathroom. The city inspectors came and the first thing they do is check the water temp at the faucet. If it is 1 degree above 120 degrees, then you fail the inspection. 120 is the regulation in every state in the US. We found 120 was not hot enough. We were running out of hot water especially in the winter because the water coming in was colder. So when they passed us and left, we turned it up to 140. We don’t have young children to worry about. Now it works perfectly and no complaints from guests about temp or running out of hot water. 140 should be plenty hot. If I were you, I’d get a thermometer and check it yourself before replacing your heater or calling a service technician. Here are the regulations for each country;

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