Insinkerator Water Heater


I’ve never liked electric hot water heaters as a lot of energy is lost in transmission from the generating source, but I’ve made an exception for this little 2-1/2 gallon hot water heater that goes under the sink of our office kitchen. It has a switch that I turn on for maybe an hour, then turn off. The water temperature can be set with the thermostat. The tank is well insulated, so it stays hot for hours. It seems a very efficient use of electricity.

In the house, we’ve had a 5-gallon electric water heater under the kitchen sink for about 15 years. It’s minimal in electric power usage, and doesn’t waste water getting from cold to hot (in pipes coming from a more distant water heater). And yes, I’ve got to get more of our water heated by the sun. It’s on my list of things to do, honest.

-- Lloyd Khan  

Insinkerator Undersink Water Heater
Model W152

Available from Amazon

Manufactured by Insinkerator

Dickinson Marine Fireplace

We live in a tiny house and love our Dickinson Marine fireplace — it does an excellent job of heating our 105-square-foot space. Watching the flames makes things very cozy on a cold day.

We generally use our fireplace beginning sometime in November through about April, depending on the weather. It uses very little propane; I think it cost us about $40 for heating this past winter. We use the 12v built-in blower when it is particularly cold or when we are trying to heat things up quickly. But forced-air heat blows around dust, which makes me sneeze, and it is a little noisy, too, so I prefer to leave the fan off when it’s not necessary. Without the fan on the heater is very quiet. For our small space and compared with electric space heaters or even central forced-air systems, this little guy takes the cake.

One nice side bonus: When the heater is on, I can place my coffee cup on top next to the flue to keep my coffee warm!

-- Derek Raedeker  

[Heater specs here. Dickinson is based in Coquitlam, BC, Canada, but they have a shipping warehouse across the border in Washington: shipping for this unit should run between $30 and $50 in the continental U.S. -- es]

Dickinson Marine Newport Propane model P-9000

Manufactured by and available from Dickinson Marine

Solar Hot Water Systems

Way back in the 70s and decades before, too, hundreds of us tried lots of ways of heating water with sunlight. Some schemes worked fine at first, but later succumbed to failures of materials and technique. Some defiantly produced only lukewarm water available only at awkward hours. Some defied the laws of physics and didn’t work at all. A few exploded. It wasn’t long before it was common to see deteriorating solar water heaters perched disconsolately on rooftops, abandoned by humiliated, exasperated owners.

Time to try again! This inspiringly-comprehensive book presents what has been learned the hard way over the past 30 years or so. Clear illustrations (many in color) show the layouts that have proved to be the best in every way. Recommended hardware is here complete with brand name and even the part numbers. Here are the most effective pipe sizes and materials and why they are chosen. Classic mistakes are attended along with their corrections. Cautions are noted; success is celebrated.

My experience in the field and 25 years at the Whole Earth Catalog tells me that every aspect has been well covered and detailed. If you follow the recommendations, your solar hot water system will be sure to work and last a long time. I consider this book as a model for collected experience on other subjects as well.

Note: a black and white version of the book is also available. I recommend the colored version.

PDF download of Table of Contents

-- Jay Baldwin  

Solar Hot Water Systems: Lesson Learned 1977 to Today
Tom Lane
2004, 194 pages
$90, or $40 for the black and white (shipping included)
Available from the author via ECS Solar Energy Systems

Sometimes available from Amazon

Sample Excerpts:

Changing sunlight into electricity (PV or photovoltaic systems) captures everyone’s imagination and the publicity causes them to contact solar contractors. Once they focus on KWH’s [kilowatt hours] saved, it becomes clear that for every $20 to $30 spent on a PV system you can save the same amount [of KWH] for $1 spent on a solar hot water system.

NEVER RUN THE INSULATION THROUGH THE FLASHING THROUGH THE ROOF DECK WITH THE PIPING. This can cause rain to run between the insulation and the piping into the home. Seal under the stand pipe before soldering around the “coolie hat.” DO NOT USE SILICONE SEALANTS.


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ProCom Unvented Propane Heater

If you have an unheated outbuilding or basement and you want to warm it cheaply with minimal installation hassles, the ProCom “Blue-Flame” ML300TBA is an interesting option. A combination radiant/passive-convection heater powered by propane, the ProCom burns cleanly and needs no vent or chimney. A bit more civilized than the brute-force, rocket-engine-style of the previously-reviewed, portable Dyna-Glo workshop heater. Granted the Dyna-Glo has the raw power to bring a very large, cold space up to a comfortable temperature within a minimum amount of time, but it is relatively expensive to run and does make a distracting amount of noise. The Procom, on the other hand, just simmers almost silently in the background.

Those who live in the boondocks may already have a propane tank in the yard. Otherwise, you can buy a cylinder of the same type that you would use with a barbecue grill, and refill it from a propane dealer or by using the cylinder-exchange service at Wal-Mart. To run the heater from a small cylinder you will need a pressure regulator that screws into the top (with a sneaky left-hand thread), plus a piece of hose with 3/8″ female connector on each end, and a male-to-male 3/8″ brass adapter (known in the trade as a “nipple”) to attach the hose to the heater. All of this stuff should be available at your local hardware store, together with Teflon tape, which you wrap around the threads before assembly. Make the joints tight, then squirt a solution of dishwashing liquid on them to check for leaks (which will blow bubbles). If you have any doubts about this, naturally you should consult a plumber. Personally, I had no problems.

Building codes and commonsense advise you to keep propane cylinders outside in case a cylinder leak occurs, which you may not notice since propane is heavier than air and collects at floor level. I made a hole through the wall for the hose and stood an 8-gallon tank outside on the deck. The only problem I found using this size of tank is that the heater’s pilot jet sometimes doesn’t relight easily when the heater is warm and the propane tank is cold (the tank gets colder during use, because of the loss of internal pressure). The instructions do recommend a full-size tank of 150 gallons or larger.

During use, the heater creates virtually no odor detectable by my nose, and because no heat is lost through an outside exhaust, it’s super-efficient. Just to be on the safe side I bought a carbon monoxide detector from Home Depot for around $20, but it has not registered any hazard. Of course any flame will consume oxygen, and for this reason alone you should crack a window a little if you keep the heater burning for prolonged periods. The heater is not recommended for very small spaces, bedrooms, or bathrooms. Be sure to follow all the instructions in the manual.

Initial setup only took me fifteen minutes. It hangs on a single (supplied) bracket, which you fix to the wall with two screws. Model ML300TBA generates up to 28,000 BTU of heat and warms my office area comfortably within about fifteen minutes, starting from 55 Fahrenheit. Since the combustion of propane unites hydrogen in the gas with oxygen in the air, the heater liberates more than one-and-one-half pints of water per hour at its maximum setting, in addition to some carbon dioxide. The water is a bonus for me, as my sinuses prefer some humidity. The heater is silent unless you buy the optional (overpriced) circulation fan. Personally, I prefer to use a ceiling fan to spread heat around more actively.

Is it really safe?

Well, consider the alternatives. A wood-burning stove is generally regarded as benign, yet can emit significant carbon monoxide through incomplete combustion if you use it in “slow burning” mode. Fragrant wood smoke is rich in tars that may be carcinogenic, some escaping into your living room while the rest circulate through your neighborhood via that convenient device, the chimney — which is not only horribly inefficient but becomes a notorious fire hazard as residues accumulate inside it.

You can see where my bias lies. For those who don’t want to install a chimney, or don’t have a municipal gas supply, or don’t want to pay a plumber to extend an existing gas line to an additional location, an unvented heater is a convenient option. Propane is not an irritant, does not cause sensitization, and has no known teratogenic or mutagenic effects. Also, unlike a wood stove, the ProCom heater contains an oxygen depletion sensor that will shut it down if necessary. Of course if you allow it to become very dirty, it may burn less efficiently, creating some carbon monoxide, like a kerosene stove, which is why you may find a carbon dioxide detector reassuring.

Your only problem may be in finding this item. A large local hardware store refused to believe that such a thing could exist. Ventless gas heater? You mean — without a chimney? “Impossible,” they told me. Even a local plumbing/heating specialty place was skeptical. But my local propane supplier told me to mail-order one from Northern Tool, known to many of us as an indispensable source for cheap Chinese hardware, which sells the ML300TBA model heater for $170, excluding external connections.

[Northern Tool also sells a natural-gas version of the ventless gas heater, which I have not tried -- Charles Platt The model reviewed by Charles (ML300TBA) is no longer available at Northern Tool or Amazon. The MD300TBA model, which we link to, seems to be the closest replacement.]

ProCom Unvented Propane Heater – MD300TBA*

Available from Amazon

EccoTemp L5 Portable Tankless Water Heater

While most tankless water heaters require expensive permanent installation, the Ecotemp L5 water heater provides hot water anywhere there is a water spigot and a garden hose. The L5 comes with a propane hose and a telephone-style shower nozzle. To set up the L5, you hang it on nail, attach the water hose, and connect the propane hose to a standard portable propane tank. The burner starts automatically when you turn on the water using the control on the shower nozzle.

My wife and I have a tiny cabin on a piece of mountain land that has a water supply, in the form of a frost-free water spigot, but no other utilities. We bought the L5 two years ago when we got tired of heating water for washing and showers in a pan on our Coleman stove. The L5 makes this glorified camping spot feel luxurious. The heater weighs about 12 pounds, making it easy to move back and forth between the spot where we wash dishes and a small enclosure I built for taking showers. When we leave, we disconnect it, drain it, and store it the cabin.

The heater uses two D-cell batteries to run its automatic igniter. In two years of summer-weekend use, we’ve not yet had to replace the batteries. The heater has two controls: a water-flow dial and a gas-flow dial. In practice, you just turn the gas dial to “max” and adjust the temperature by varying the water flow. When adjusted to a decent temperature for a hot shower, the flow is perfectly adequate.

The heater must be used outdoors. Conceivably, you could mount it to the outside of a cabin and pipe the hot water inside. The water outlet accepts the same kind of flexible water supply hose you use to connect a sink’s faucet to your household water supply.

The L5 is not the only on-demand portable water heater. Coleman’s table-top unit uses small, disposable propane canisters, and has a built in pump, allowing it to be used without a pressurized water supply. The pump’s battery must be recharged every 40 gallons. Available accessories for the Coleman include a shower handset and adapters for bulk propane containers and pressurized water supplies. The Coleman unit’s built-in spigot makes washing hands and dishes more convenient than the L5’s shower handset, and it has a special mode for producing 160 (F) degree water for hot drinks. However, it has 20% less heating capacity than the L5 (which is rated at 37,500 BTUs) and costs substantially more, especially with accessories. Another option, the Zodi travel shower, also uses a battery-powered pump, but provides only 10,000 BTUs and lacks the instant-on feature of the L5 and Coleman heaters. Both the Coleman and the Zodi are free-standing, and do not require a place to hang them. The Coleman costs about $185 (plus $30 for the bulk propane adapter, $25 for the water supply adapter, and $15 for the shower handset), the Zodi $130, and the L5 $120.

In the two years we’ve had the L5, we’ve had a couple small problems. We had to replace the short hose that connects the heater to the shower handset. More recently, the handset itself broke when we left it outside on a very cold night and the water in it froze. Occasionally, the burner will go out in a high wind. On the whole, however, the L5 has been very reliable and convenient. Besides luxury camping, I could see the L5 being useful in a potting shed or an outdoor kitchen.

-- Tom Sackett  

EccoTemp L5 Portable Tankless Water Heater
Manufactured by EccoTemp

Available from Amazon

TheraTherm Digital Heating Pad


Finally a digital heating pad that can maintain a temperature you set — not just one of three arbitrary settings. This heating pad has a range from 86 to 166 degrees F that can be adjusted in 2-degree increments. I don’t have any particular injury or ailment, other than occasional mild back pain, but I use this unit daily (actually nightly). This is probably not recommended use, but I have developed the habit of sleeping with a heating pad. Instead of running all the time like older units, though, this one has an auto-off function that lets you set it to stay on up to 60 minutes at a time. Also it only turns on the heating coils to bring it up to temp and when it falls below temp. Once it reaches the desired temp, it shuts off. The heat generally continues to rise 2-3 degrees, peaks, then starts to fall, then kicks back on. And so it cycles for the amount of time you program into it (the default is 30 minutes). I prefer 118°, which seems to work best for me. You can also switch the display to a ‘monitor mode’ and see the actual temp it’s reading from the pad instead of what you’ve set the thermostat to. I have no idea about the “moist” aspect of the heating pad, since I only use it as a dry heating pad. At about $60, it is a bit expensive if you’re used to the $20 pads. Also the cord to the controls could be longer and there’s no back-light on the controls, so it’s harder to use in total darkness. But once it’s set at night, I don’t have to fiddle with it or remember to turn it off anyway. The pads come in various sizes. The one I have is the 14″x14″ blanket pad.

-- Jay Harrison  

TheraTherm Digital Heating Pad
Manufactured by Chattanooga Group

Available from Amazon

Toasty Feet Insoles


I live in Minnesota in a 1920’s house with newspaper for insulation, and have not been able to get rid of cold feet — until now. These insoles are the same thickness as normal shoe liners but they have an aerogel in the sole. Like normal shoe liners, these come over-sized, so you cut them down to your shoe size using the templates printed on the soles. I have used them while wearing several different styles of shoes from dress shoes to work boots to tennis shoes to mukluks and ice skates, and have not noticed them shifting inside the shoe.

I have noticed a little bit of compression after wearing them 12 to 16 hours a day for two months, but I have not noticed a difference in thermal performance. On my wife’s pair the insulation layer has started to separate from the padded layer and she says they do not make her feet as warm as they did when she first started wearing them a couple months ago. But she shifts them between shoes much more often than I do. These insoles are cheap enough that you can buy multiple pairs and avoid moving them around, which should help maintain their integrity longer. My pair looks like it will last a few more seasons and I plan on taking them out when temperatures get above 10 degrees or so.

-- Bryan Schmidt  

Toasty Feet Insoles
Manufactured by PolarWrap

Available from Amazon

FTM – FS24 Free Standing Heater

An engineer friend introduced me to the virtues of ABS plastic, which is extremely strong, does not splinter when you drill or saw it (unlike wood or acrylics), comes in a variety of thicknesses of 4×8 sheets (just like plywood), and usually is smooth on one side with a textured finish on the other. We use it to make everything from little brackets and shelf supports to complicated containers for transporting fragile equipment. You don’t have to paint it, and its consistent texture makes it very easy to shape. If you live near any large urban area, there will be at least one plastics supplier near you that will sell it to you by the sheet.

The best part of fabricating things with plastic is that you can bend the plastic. When you work with wood, you have to join two pieces (mitering, gluing, whatever) to make a right-angle. With the FTM heating device, I can make a controlled bend within a couple of minutes. Sponge it with water and the plastic stiffens, seemingly just as strong as before. It’s like large-scale origami.

Other plastic benders may be available online, but the Cool Tools Rules state that I may only recommend the tool that I have used personally. So, this is it, even though I must warn you (shock! horror!) you cannot buy this online. You can visit the manufacturer’s web page and view the specifications, and then if you want to purchase your own bender, you’ll have to pick up the phone and order it, with your credit card, from a human sales person.

FTM – FS24 Free Standing Heater
Manufactured and sold by
The Fabricator Source

AquaStar Tankless Water Heater

I have lived on a boat since I was 13. We have tried just about every way of heating water (including one kettle at a time on a wood stove). Since boats usually don’t have room for a big water heater, nor the natural gas hookup, we usually had a hardly-functioning on-demand propane water heater. They were infernally breaking down. However these “instantaneous” water heaters have finally come of age due to market pressures, so now you can buy a highly efficient mainstream tankless heater for home use.

I now have a Bosch AquaStar 125HX. Not only is it smaller and more efficient than any water heater that uses a tank, it gives endless hot water at good pressures, and has worked flawlessly in a marine environment for the last three years on my houseboat. This water heater instantly lights up a propane heating system automatically the moment I turn on the hot water, yet it does not need a power cord (important if your power goes off, or if you aren’t on the grid). It does this by cleverly generating electricity from the water pressure in the pipes to spark a piezo igniter.

There is a whole AquaStar line from large ones for multi shower households, to the smaller ones like mine. Some are made to work in line with solar radiant heating, some with propane, some with natural gas. I really like the HX model because it works with no outside power source or pilot for ignition, making it very efficient, safe and reliable. They cost more than standard water heaters (mine was $550) but they pay for themselves fast in power bills since you don’t have to keep a large tank of water heated all the time; you only make hot water exactly when you need it.

I would absolutely use one of these even if I lived on land with access to a gas line. The hot water never runs out (which would be great in a household with a lot of people, or if you just like long showers) and its more efficient because its not heating a whole tank of water all the time.

-- Alexander Rose  

Available from Amazon