What’s the best temperature to set your water heater to?  There’s no single great answer.  The American Society of Sanitary Engineering Scald Awareness Task Group recently released a white paper on this topic, which essentially says that there is no perfect temperature to set you water heater to.

What’s a safe temperature for water?

On the side of most water heaters you’ll find a warning that says water temperatures of 125 degrees Fahrenheit can cause burns or death.  To be safe, the water coming out of the plumbing fixtures in a home shouldn’t be any hotter than 120 degrees.   The handy photo below (courtesy of Charles Buell)  shows how fast second and third degree burns can happen at temperatures that any new water heater is capable of producing.

Just turning down the temperature at your water heater until you’re at a safe 120 degrees isn’t enough to solve potential scald hazards because the thermostat on a water heater isn’t designed to keep the water at a constant temperature; it’s just designed to keep the water within a certain range of temperatures.  Seattle home inspector Charles Buell has posted a couple different blogs explaining how this works – one explaining how water heaters sometimes run out of hot water faster than they should, and another on the different temperatures that will be produced by a water heater during different stages of the heating cycle.

During a recent inspection of a large home that was heated with two high-efficiency water heaters, I found quite a range in temperatures.  When I first turned the hot water on at a fixture, the water temperature started out cool; this was because the water in the hot water pipe had cooled down to room temperature.  As the hot water from the top of the tank arrived at the plumbing fixtures, the water temperature rapidly jumped up to nearly 154 degrees – this was hot enough to cause first degree burns instantaneously, and second degree burns within one second.

The water only stayed at this temperature for a few seconds; it quickly dropped back down to about 135.  While there was a tempering valve installed to mix cold water in with the hot water right at the water heater outlet, it wasn’t enough to completely control the water temperature at the fixtures.

Minnesota has no requirements for residential water temperatures.  Anti-scald devices are required in all new or remodeled showers or shower-bath combos in Minnesota (4715.1380 Subp. 5), but this does nothing to address the final temperature of the water coming out of a fixture.   Anti-scald devices only help to prevent people from getting scalded by a sudden swing in temperature while taking a shower.  With old shower valves that didn’t have the anti-scald feature, if a toilet would flush while someone was taking a shower the pressure on the cold water line would drop, quickly increasing the water temperature at the shower.

Lower Temperatures Allow Bacteria Growth

It seems as though the solution to help prevent accidental scalding would be to turn down the temperature at the water heater to say, 115 degrees, but lower temperatures actually create other problems.

At temperatures below 135 to 140, Legionellae bacteria, which is responsible for Legionnaires’ Disease, can survive and even multiply in the water heater tank.  Estimates by LegionellaPrevention.org say that up to 600,000 cases of Legionnaires’ Disease are misdiagnosed as pnemonia each year, because this is something that isn’t tested for in hospitals.   The diagram below shows the time it takes to kill Legionellae Bacteria at different temperatures.

To help prevent bacteria growth, the ASSE recommends keeping the water in your water heater tank at about 135 – 140 degrees Fahrenheit.

Of course, this creates a scalding hazard.

So What’s the Answer?

To help prevent bacteria growth and to lower the risk of scalding, have a plumber install a tempering valve and crank up the temperature at your water heater to about 135 – 140, as ASSE recommends.  Last year I wrote about how I installed a tempering valve on the hot water outlet at my own house in order to get more water out of my water heater.  These valves would be a good thing to install in every home.  A tempering valve allows you to keep the water at a dangerously high, Legionellae-killing-temperature inside the water heater tank, yet it mixes cold water in with the hot water right at the outlet, making it so you don’t get this hot water at the rest of the fixtures in your home.

As I mentioned in my story about the recent inspection with dangerously hot water, a tempering valve won’t guarantee safe water temperatures, but it will get you a lot closer.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector

Do you know what type of smoke alarms you have in your house?   There are two basic types of residential smoke alarms – ionization and photoelectric.  The vast majority of smoke alarms in use today are the ionization type, but they’re being questioned more and more as a valid detection method; today they’re no longer allowed as the only type of residential smoke alarms in Iowa, Vermont,  and Massachusetts.

Why all the bad press about ionization smoke alarms?

One of the major problems with ionization smoke alarms is that they give off too many false alarms – mostly from cooking and showers.  When a smoke alarm goes off every time someone cooks bacon, people remove the battery or take down the smoke alarm. Manufacturers require them to be installed away from kitchens and bathrooms, but there is no hard and fast rule for clearance requirements across different manufacturers.  Some cities, such as Minneapolis, have implemented even stricter requirements for ionization smoke alarms; they require smoke alarms that are within 20′ of a cooking appliance to either be of the photoelectric type, or to have a hush button.

Recent statistics show that in 24% of home fire deaths, smoke alarms were present but did not sound; in half of those cases, there was a missing or disconnected battery.  This is a common problem that I find all the time while doing Truth-In-Sale of Housing evaluations, and the reason people always give is that the smoke alarm goes off every time they cook or shower.

The other problem with ionization smoke alarms is that they take a long time to respond to a smoldering fire – they’re tens of minutes slower than photoelectric alarms (page 17).   Estimates show that at least one third of home fatal fires involve a significant smoldering period (page 14).   This is the major reason that there is such a push to replace ionization smoke alarms with photoelectric smoke alarms.  The diagram and text below comes from a handout published by the CPSC, showing how a photoelectric smoke alarm will give occupants much more time to escape in the event of a smoldering fire.

In the event of a smoldering fire, a photoelectric smoke alarm clearly outperforms the ionization type.  So why do we even have ionization alarms?  The main reason is cost.  Photoelectric smoke alarms typically cost about twice as much as the ionization type.  The other reason is that ionization smoke alarms will outperform photoelectric alarms in the event of a fast moving fire.  The faster reaction time can be measured in tens of seconds, but in the event of a fast moving fire, these are precious seconds.  The diagram below, again from the CPSC, helps to illustrate this.

Most Smoke Alarms are the Ionization Type

I’ve been hearing more and more about this push, but after recently listening to an impassioned speech on the benefits of photoelectric smoke alarms over ionization alarms, I started taking an informal inventory of the smoke alarms that are installed in Minnesota homes.  Over the past few weeks, I’ve taken a close look at every smoke alarm in every house I’ve inspected to get an idea of what’s the most common type used in Minnesota.  Out of the dozens of smoke alarms I’ve looked at, I found one dual-sensor smoke alarm, which employed both ionization and photoelectric technologies.  The rest of the smoke alarms were the ionization type only.  I didn’t come across a single photoelectric unit.

To know the difference between ionization and photoelectric alarms, you need to take the smoke alarm down and look at the back.  Ionization alarms all contain a trace amount of a radioactive material, Americium 241.  They’ll all have a warning about this on the back side.  Click on any of the thumbnails below to see a blowup of the text on the back side of a smoke alarm - I marked up the labeling that indicates these are ionization alarms in every photo.

Minnesota Requirements

Minnesota currently has no specific requirements when it comes to ionization vs photoelectric smoke detectors.  Smoke alarms are generally required in bedrooms and in common areas on every level of the home in Minnesota, and they need to be hardwired and interconnected when possible.  You can read the full requirements for smoke alarms in Minnesota here.

My Recommendation

I recommend installing both photoelectric and ionization smoke alarms, or smoke alarms that use both technologies called dual alarms.  Some people argue that these alarms shouldn’t be used because there could be more nuisance tripping due to the ionization sensor, which would cause the occupants to disable the smoke alarm.  While this is obviously a possibility, proper placement of smoke alarms and better education about how they operate is the best way to make a home safer.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector

Chandeliers above bath tubs are apparently all the rage today.  A few weeks ago I somehow ended up inspecting three houses in a row that had chandeliers installed above the bath tubs – one in Chaska, one in Saint Paul, and one in Victoria.  They all look great, don’t they?

Shortly after I posted these photos on the Structure Tech Facebook Page, Debbie Nelson said she’s been seeing this trend for the last five years or so.  She even gave me a couple links to web sites promoting this look – houzz from almost a year ago, and HGTV from about five years ago.

I think this is a great look, but as a home inspector I’m going to be a wet rag and say these are all improper installations.  The diagram below comes from Code Check Electrical 6th Edition.  This book is based on the 2011 National Electric Code (NEC), which prohibits any part of a chandelier from being within the shaded region shown below.  This comes from section 410.10(D) of the NEC.  The idea is that you’re not supposed to be able to stand in a wet tub and change a light bulb at the same time.

This doesn’t mean you shouldn’t install a chandelier above your bath tub… but you’re supposed to have a very tall ceiling to do it, and even then, the light should be rated for a wet or damp location.  The image below shows a chandelier rated for a damp location – you’ll notice that the bulbs are completely enclosed.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector

For about the last twenty years or so in Minnesota, it’s been standard practice to seal up attic bypassses; little passageways for conditioned household air to leak in to the attic.  Attic bypasses are also known as attic air leaks.  It’s important to seal all of the bypasses in an attic, because air leaking in to an attic has a far greater effect on attic warming and heat loss than just missing insulation.

I’ve been doing a lot of new-construction inspections or one-year warranty inspections on new construction houses, and I’ve started to notice a new attic bypass that seems to be completely ignored by some builders and insulation contractors.  At a recent new construction inspection in Woodbury, I actually had a good suspicion that I would find this defect as soon as I pulled up to the house and looked at the frost covered roof.

That dark spot on the roof shows a warm spot where the frost never accumulated.  Click on the photo for a larger version.

This localized warm spot on the roof is the result of a tube that was fed in to the attic as a chaseway for future wires, such as satellite cables or antenna cables.  The other end of this tube is located in the basement utility room, near the data cable box - they call this a data tube or a tech tube, and I think it’s a great idea.  What better way to get low voltage wires from the basement to the attic?  The only problem is that some installers seem to forget that this is another attic bypass that will leak warm air in to the attic.

Just as every little hole and crack that allows air in to the attic needs to be sealed off, so does this relatively large opening.  Thankfully, the fix for this situation is very simple; just cap the end of the pipe.  This can be done pretty much any way you see fit – I’ve seen it done with both electrical tape and duct tape, and it works fine.  If you have a newer home, this is just one more reason to break the seal on your attic access panel.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector

If you see black stuff covering or growing on the roof sheathing in your attic, it’s probably mold.  It’s never fun to find out that your house has mold, but the fix for mold in the attic is usually quite straightforward, and doesn’t involve the services of any ‘mold remediation experts’.

There are a lot of folks in the real estate industry, including home inspectors, who get very excited when the word ‘mold’ comes up.  I actually sat through a seminar where we were told to never even use the word mold, because “you never know what something is without testing it.”  I couldn’t help pointing out that by that logic, we should no longer call houses ‘wood framed’ houses unless we test the material to verify that it’s actually wood.

What causes mold in an attic

When mold grows in an attic, it’s caused by a moisture problem.  Period.  Some moisture sources are obvious and have a huge impact – bathroom exhaust fans, kitchen exhaust fans, clothes dryers… they all pump moisture out of the house, and they should never be vented in to the attic.   Everyone knows that, right?

The less obvious moisture sources are attic bypasses; air leaks that allow relatively warm, moist air from the house to get in to the attic.  To reduce the amount of moisture getting in to an attic, the attic air leaks need to be sealed off.  Covering these air leaks with traditional insulation doesn’t stop the air movement; there needs to be some type of air barrier installed, such as foam insulation or caulk.  These attic bypasses show up quite clearly with an infrared camera, but any well-trained insulation contractor will already know exactly where to look for these.

Photos of Attic Bypasses / Attic Air Leaks

I’ve accumulated about a bazilli0n photos of attic bypasses over the years, so included below are a few of the most common places you’ll find attic bypasses in just about every Minnesota house built before 1991.  In all of the photos below, I’ve pulled the insulation away to reveal the bypasses; you won’t find any of these in your attic without moving insulation around.  For the record, home inspection standards of practice don’t require the home inspector to move insulation… so don’t be surprised if your home inspector didn’t mention any of this stuff.

Any time small cables or wires pass through the top plates of walls in to the attic, the holes for the wires should be sealed up.  When they’re not sealed, they leak air.  Do you see how some of the insulation in the photo below has been darkened?  It’s not mold.  This is the result of years and years of air leaking through the insulation; the insulation acts like a filter, and traps all the dust in the air, turning it black.  Even though these tiny holes don’t seem like a big deal, having them all over your attic can have a huge effect.  Sealing these gaps can be easily accomplished with a can of foam insulation.

Larger penetrations in to the attic, such as plumbing vents, also need to be sealed.  Again, foam in a can works well.

The first place I always check for attic air leaks is around the furnace vent; if there is air leaking in to the attic around this chaseway, there will surely be air leaking everywhere else.  In this first photo, the darkened insulation is a dead giveaway that there is a lot of air leaking through here.  Foam insulation wouldn’t be an appropriate repair for this location – the vent is supposed to have at least one inch of clearance to anything combustible.  In the photo below, installing a small block of wood to fill the gap at the bottom (maintaining a one inch clearance to the vent) and then sealing the entire assembly with high-temperature caulk would be a good fix.

Here’s another furnace vent – this one is completely missing the sheet-metal collar.  I could see right down in to the walls after pulling the insulation away.  This is very common.

Here’s a huge bypass around a furnace vent; the chaseway that leads down to the basement was large enough for a person to fit through, and it was basically wide open at the attic; they just had a piece of fiberglass insulation covering the top.  You can clearly see the basement ceiling from inside the attic.

The space around masonry chimneys will often be a source of air leakage.  If the chimney is being used for a wood burning fireplace, there needs to be a two-inch gap to combustible materials.  Sealing these air leaks will require the use of high temperature caulk and sheet metal.

As I mentioned in my blog about evil recessed lights, they can be a huge source of attic air leakage.  Notice all the light pouring through this fixture; the light equates to a lot of air leakage.

When additions are put on, the transitions between the new and old portions of the house are often sources of air leakage.

Whole-house attic fans can be a major source of air leakage in to attics.  These are fans that are designed to be run in the summer only.  The photo below shows light leaking through the attic fan, which means a lot of air is leaking through as well.

Probably the largest attic bypass that I commonly find is the one above the stairway to the basement on old ramblers.  All of the wall cavities are wide open to this space, and nothing above it is sealed off.  This is a bypass that’s large enough to fit a small family in to.  Other areas where ceilings drop down in older houses will be areas to look for bypasses – especially over bath tubs and kitchen soffits.

Finally, the space below the knee walls in old one-and-one-half story houses can be a major source of air leakage.  The way to repair this is to have solid blocking installed underneath every joist cavity, and have it made completely airtight.

This is certainly not an all-inclusive list of the places to find attic air leaks, but it should be enough to help you understand what an attic bypass is.  This is how air leaks in to the attic.  When all of these air leaks are perfectly sealed and a vapor barrier is properly installed in the attic, the attic interior will stay dry.

What if the air leaks can’t all be sealed?  Sealing off all of the attic air leaks is nearly impossible to do without completely removing all of the existing insulation. I’ve actually recommended doing this many times, but before starting with such a drastic measure, it’s a good idea to check the obvious stuff in the house first.  If the house is too humid, fix it.  A large percentage of attic moisture problems are caused by whole house humidifiers.  This fix for this situation is a no-brainer; turn the humidifier off.

Does adding more ventilation fix the problem?  Attic ventilation is required by the building code, but it’s not a magic elixir.  Air moving through an attic will help to remove moisture, but this isn’t the cure for a moldy attic.  I’ve heard many people conclude that an attic mold or moisture problem was caused by lack of ventilation, but that’s a little like saying a hangover was caused by not taking enough Advil before going to bed.  Adding more ventilation to an attic is just a way of dealing with the symptoms, and it doesn’t always work.

So what needs to be done about the existing mold?  It depends on who you ask.  If you talk to someone who has a financial interest in cleaning up the mold, they’ll tell you it needs remediation.  If you ask someone who could get sued for not recommending professional remediation, odds are they’ll tell you to have professional remediation.  Other people might argue that once the air leaks between the house and attic have been sealed off, it won’t matter what’s in the attic.  As long as the roof sheathing isn’t rotted, I tend to agree.

For the record, sealing off attic bypasses is also one of the most effective ways of preventing ice dams and preventing frost accumulation in the attic.  The Minnesota Department of Commerce has an excellent guide to finding and repairing attic bypasses, which gives more detailed information on how to find all of these bypasses and how to fix them.

Reuben Saltzman, Structure Tech Home Inspections - Email - Minnesota Home Inspector