Alternative energy advice from Ask Jeff Yago. Volume #25

Ask Jeff Yago
Solar & Energy-Related Issues

By Jeffrey Yago, P.E., CEM
Jeff Yago

Sorry. Jeff no longer answers questions online

Wood cook stove

I am looking for plans to build a kitchen wood-cook stove.

Thanks for your help



Here are is a link to plans for building your own wood stoves:

Good Luck!

Jeff Yago

Pre-catalytic wood stove conversion


I just bought a 1972 Vermont Castings wood stove called a Vigilant. It is a big empty cast iron box with an eight inch flue and solid no-glass double doors. What do I need to do to it to enable secondary combustion or gasification?



Sounds like you have a real classic and built to last. Unless you are required in your area to add this, I would not waste my time on this stove. If you decide to do anything, the easest will be one of the kits that fit into the flue on top of the stove.

Good Luck,

Jeff Yago

Old Hot water heating system

Dear Jeff,

I have a 4,000 sq ft Victorian home that built around 1900. I purchased it 2 years ago. It came with aluminum siding and a new roof with a ridge vent. I soon learned that it had no insulation in the attic or walls so contracted blow-in insulation and soffit and proper vents to make the ridge vent function properly. We also replaced 11 of the 43 windows and tightened up most of the drafts. However, my oil bill is still about $3,000 per heating season. I was going to update the hydronic hot water generator after last season but the oil company stuck me with a full tank in April. So here I am spending another 3K on oil.

My dilemma is this, the hot water system consists of a 4 inch supply header (around 60 feet long) with individual feeds to each radiator that go back through another 4 inch return header. I’m sure this is great for getting the same temperature water to all of the radiators but I’m concerned that the modern generators aren’t suited to Header type systems. I have a summer cottage at the shore that has a modern Weil McClain generator and noticed that there is no such header. It works great making all of the radiators quite hot and heats the house very quickly. If I go to a modern High Efficiency gas system, will I have to change the whole piping arrangement ?

I should also point out that I invested about $600 on piping insulation and insulated both supply and return headers as well as the accessible portions of the branches to the radiators in the basement and crawl spaces. I figure most of the energy I’m wasting is heating up this large volume of water in both the generator (probably built in the 40’s -General motors, Delco heat) and headers.

Thanks for your help.


Larry W.
Haddonfield, NJ


Sounds like you have a real problem.

You first need to decide if you want to stick with oil or switch to gas. I assume your existing oil boiler is very old and past time to replace. Many boilers designed for gas firing can be converted to oil or even use both, but if it is over 20 years old it is time to replace. Your piping headers and piping distribution layout is a function of the heating system design, not the boiler.

You did not say if your system has a pump, but most systems using large headers in residential systems are designed to operate without any pumping, so most likely this is a very old system which did not use pumps. If the radiators are OK, I would scrap the boiler, headers, and replace with new high efficiency boiler, zone valves, and circulating pump. With a pump your piping will be in the 1″ TO 1-1/2″ size range at the boiler, and most likely 1/2 to 3/4″ run-outs from the mains to the radiation. With a pump system, you can have several zone valves and wall thermostats to allow having different temperatures in different rooms to save energy. Finally, decide if oil or gas in your area will be your best long term best choice and go with that fuel type boiler.

Good luck,

Jeff Yago


Thanks for your input. Here are some more specifics about my system that should clarify things:

Yes, there is a large circulator pump on the return side of the boiler. It apparently forces hot water out and into the main supply header. The supply header runs the length of the house 4 inch most of the way and then 3 inch for the last 15 feet. Then 1 ” and 1 1/2″ branches go to each individual radiator. I have to say, this seems like a good system to evenly distribute the hot water to all of the radiators. And I have to ask, without a header, how is this accomplished ? Do modern systems run like a daisy chain, with each successive radiator downstream from the next ? Doesn’t that make the radiators early in the chain too hot and those at the end too cold ? What I was hoping to hear from you is to be able to just replace my boiler with a new Modern (I have gas service in my house now) gas high efficiency boiler and still use the header system for distribution. Especially since the piping is now freshly insulated. I also can’t replace the run-outs to the radiators with smaller piping because those pipes are mostly buried in the walls. Thanks again for your help.



I was trying to say that most of todays systems do not require large header piping which saves pipe and insulation costs. For most residential hydronic heating systems, a 1-1/2 to 2″ main piping header is more than large enough to handle any water flow a typical residential circulating pump can handle. You will never see a 4″ main header pipe today unless the facility is a school or large office with much larger boilers and circulationg pumps.

I still bet this system was originally designed to operate by gravity flow (heat rises, cold falls) without a pump. Many of these older systems worked this way by using over-sized piping. If this piping is in good condition, the only real problem is the higher heat losses due to the larger pipe surface area and related higher pipe insulation costs. If this piping is in good condition, you can use almost any size pump and boiler without any heat distribution problem. However, if it is old, you better hope you never have a leak as this old piping is almost impossible to repair due to thinning pipe walls or corrosion. Once you try to un-screw a fitting something else will break or leak and it never ends.

Good Luck,

Jeff Yago


A fellow co-worker introduced me to one of your articles. I am totally hooked!

I am an older C.Engr. undergraduate student in Texas.

Qstn 1: Would you have a reading list that you think would be a good start to self-educate myself on solar installations.

Qstn 2: What advice can you give me on how I might connect up with an installer to “hang-out” w/ them for a Summer? I’d like to be part of a project for hands-on experience.

Thanks for the inspiration!!!



Glad you like the articles. My book is now out of print but you can still find a few copies on Amazon. There are a few solar books listed on the BackWoodsHome Bookstore that I reviewed for the magazine and can recommend.

There are a few solar installers in Texas you might hook up with. Check the NABCEP website for certifie solar installers listed by state. Any NABCEP certified installer has had to have years of experience plus take a very dificult certification test and will really know what they are doing. Learn for the best if you are interested in the field regardless of age.

Good Luck!!

Jeff Yago



I want to install a simple gravity fed hot water tap in my remote cabin. I am not electrified at this location. My idea is to have a water containment vessel (probably not sealed) above the heat source and copper tubing running out of the bottom of the vessel dropping to about 15 coils around a wood stove pipe. When I open the tap (which is at the lowest point) the water flowing around the coils will heat to a temp relative to the amount of heat the stovepipe is generating. Will this system work, or will the water thermosiphon back into the vessel and provide me no water at the tap? Do I need a sealed system with an inlet and outlet in the water vessel to circulate water as it heats? Thanks for the help.

Richard P.


What you described is not a thermo-siphon system, you are just passing the water around a hot pipe when you open the lower faucet and this is not safe. Without water flow, the water in the copper pipe wrapped around the stove pipe will quickly heat up and turn to steam, then “shoot” out of the tubing and back into the elevated tank. For a thermo-siphon system to work and not overheat, you need a constant water “flow:” around the copper piping and up into the side of the tank near the top (but still below water level). The bottom end of the copper coil is connected into the bottom of the elevated tank which has to colder water (heat rises). Your hot water supply piping to faucets should be a separate pipe connected near the top of the tank (also below the water level). As the water is heated in the coil, it will rise and enter the top of the tank, while colder water enters the coil from the bottom of the tank. If you decide to make this a closed system and under pressure, you will need a separate temperature relief valve and a pressure relief valve, but I recommend that you keep it simple and not pressurize the tank. Make-up cold water can be a separate cold water line connected near the bottom of the tank using either a manual valve or a “commode” type float valve to let more water in as the water level drops.

Be safe,

Jeff Yago

LED plant lights


I was wondering if LEDs will work like fluorescent lights for growing plants indoors?

Thank you,



Actually, there have been several recent studies related to growing plants using LED lights verses other lighting types. If interested, check out this link – – – >

There are some LED lighting fixtures starting to hit the market for LED greenhouse lighting if you do some internet searches, and so far it looks like there is little difference between the growing effects of more common HID greenhouse lights and the new LED lights. You may want to check the effects of color on growth as it is my understanding that red and blue LEDs provide the best color frequencies for growing.

Good luck,

Jeff Yago

Solar on the coast


I’m new to solar and I’m having trouble finding information on appropriate panels for a Northern California home right on the coast. My husband is convinced nothing will hold up to the salt air. A guy at Real Goods took his side. Is there anything available or coming in the near future that will last on the coast? A typical outside house light corrodes away in 2-3 years!




Having just returned from a month in Hawaii on a project for the military I know what you mean about salt air. However, solar systems are very popular all over California and Hawaii and other coastal areas and you just need to make sure you use the right materials.

Quality solar modules are tempered glass with heavy aircraft grade aluminum frames. Although salt air is hard on aluminum, these frames are thick and should give many years of service. You can also specify coatings for aluminum that resists salt air corrosion. Solar module mounts can also be ordered made with the same grade aluminum and assembled with stainless-steel bolts. This avoids galvanic-corrosion problems when using different metals together. Finally, ordering solar modules with non-metallic gasketed junction boxes and connecting with copper wiring in flex plastic sunlight-resistant conduit should help with any corrosion of wiring components.

If you stay with quality components made in the US and indicate you are in a salt air environment when ordering should allow you to have a system that will last many years.

Good luck,

Jeff Yago

Making steam heat more affordable


I’m looking for a way to make steam heat more affordable. I recently read about an option to use an outdoor wood furnace with a furnace coil. From what I understand I would have to run a water pipe from the outdoor furnace to the steam boiler. What are your thoughts on something like this?




Not sure you are going the same direction as the rest of the world. Steam heating systems are being phased out everywhere except large central utility size boiler systems. They are much more expensive to maintain then hot water systems, and very hard to prevent leaks. Makeup water must be treated to avoid sediment buildup, and very difficult to provide temperature zoning. Steam boilers can be dangerous if the relief valve sticks, and some states require yearly safety certification inspections.

The outdoor wood furnaces you are referring to are hot water systems, not steam systems, and are designed to have hot water piped into the home and either connected to a system of hot water radiators in each room or piped to a hot water coil in the supply ductwork of a forced air furnace.

You would have to convert your steam system over to hot water heating first, and in older systems this could be very expensive. Most of these older steam systems have steam and condensate piping that is very old, and if you try to change a fitting you will find the pipes just break off.

Maybe its time to change your heating system to something more efficient and that requires less maintenance?

Jeff Yago

Info on solar basics


I’m about to purchase a small stand-alone system from ecostar solar. It will have 5 130W tricrystalline panels (I can’t find much info about them?) I just need to power a 19″ TV and a few lights in our home as we work our way to full independence. It will be non grid-tie, but the guy said an electrician could wire it into the panel (on the side of house) to power those two rooms only. Not sure if I need a permit for that? He said no.

Anyway, my question relates to mounting of these 130W panels. I’ve included a picture I found on another site and that is how I will have to lay them out (head to head) but mine will be mounted along the top of our block wall in the back. Side of pole mounting seems safest so no neighbor will complain. Will there be a power loss or problem with wires when I mount them as pictured. I haven’t seen many people do it like this.

Thanks again,

Tom B


Solar modules can mount in any position and any orientation. They can be located remotely from home, but wire resistance will limit distance due to voltage drop. Usually up to 100 feet is not a problem if you go with larger wire size than required just to carry current, but longer wire runs will require very large wires. You will not be able to connect into utility grid for more reasons than I can describe here, but mainly because of small array size. Yes, you could power other loads in your home, but at 650 watts peak I think you will find this is more trouble than it is worth, and the battery bank will keep cycling from solar charging to utility grid charging since the loads will exceed system capacity. I do not agree with the advice you have received so far, and suggest keeping this a stand-alone emergency back-up type system for only a few select loads unless you add many more solar modules and a larger inverter.

Good luck,

Jeff Yago

Solar power school

Dear Jeff,

I am really wanting to learn how to install solar power in houses. But it is so hard to find a a place that teaches it besides going to one out of state. Do you know of any in Kentucky?



There are several solar related groups in Kentucky. Follow this link for several solar training programs scheduled for you area during the next several months. (2008)

Good Luck!

Jeff Yago

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