Introduction: Energy-Efficient Radiator Cover

Originally, I wanted to build a radiator cover that would protect my daughters from our cast-iron, steam radiators. Steam radiators get much hotter than hot water radiators, and I was concerned that they would get burned. As I researched different designs, I found a lot of discussion about whether you are increasing or decreasing the energy efficiency of your radiators by covering them.

Both sides made valid arguments, but I needed to cover my radiators to protect my children. I decided to incorporate all of the best ideas I had found and a few of my own into one design.

Step 1: Efficiency and Insulation

Efficiency

Some people say you are preventing a radiator from transmitting heat to the air and surrounding area when you cover it. Other people say that because the hot air coming off the radiator goes straight up, a bare radiator is an ineffective way to heat your house.

Radiators do circulate some hot air around the room, but the majority of the heat is transmitted via radiation. Because most radiators are on the outside walls of a house, a lot of the energy is wasted warming an exterior wall. Many sites suggest insulating the backside of the radiator with a foil insulation to reflect the radiant heat back into the room. This is a smart thing to do even if you are not going to cover your radiators. If you plan to use your radiator cover as a shelf, some people suggest lining the underside of the cover's top with this insulation to keep it cool.

Radiator cover efficiency
Improved Air-Flow
Benefits of covers


Insulation

There are many different types of foil insulation, but ideally you just want something with a foil coating and a thin insulation backing. I actually got my insulation at Lowes, but I really like the selection at insulation4less.com

Excellent selection of insulation types
Foil bubble Insulation

Step 2: Covered Vs. Uncovered

These are some animations I made to demonstrate the benefits of having a radiator cover like the one in this instructable.

Uncovered Radiator
Without anything around your radiator, the radiant heat goes in all directions, including to the cold exterior walls. The air around the radiator is warmed, causing it to rise and the displaced air draws fresh, cool air from below. The warm air goes straight up the wall to the ceiling and will eventually mix with cooler air to warm the room.

Covered Radiator
With a radiator cover lined with foil insulation, you can reflect the radiant heat away from the exterior wall, and throw it further into the room. The normal convection air flow around the radiator can be directed out into the room where the hot and cold air can mix more effectively.

Step 3: Selecting a Style

Typically, radiator covers have a metal mesh on the front to allow heat to pass through. I really liked the metal grills that I found at Barker Metalcraft , but I figured covering hot metal with other hot metal was not making it any safer for little fingers. I decided to make an all wood cover based on the styles I liked best.

I liked the Mission style best because it still looks like a radiator and it allows air and radiant heat to flow freely out of the slats. I also liked the idea of a vent at the very top of the hollow so that no heat would get trapped inside the case. I wanted to have a design that encouraged convection currents and possibly directed them out into the room where the heat was needed.

I used these sites for ideas:
Wolf Radiator enclosures
beautifulradiators.com
myhomeus.com

Step 4: Design

I made my cover mostly out of what is labeled "white wood" at the home stores. According to a few sites I have seen, it could be many different types of wood, but they lump it all under the name "white wood" so that they can sell anything that is available as one product. I think it is usually Spruce, which is what this looks like to me. I found a lot of pieces with tiny little knot holes and many knots that are about the size of a Lego block peg. Take your time and select the straightest pieces you can find. If you settle for imperfect wood, you will be sorry later and your project will suffer.


Update: I found a great article on About.com with information about what they call SPF (Spruce, White Pine, or Douglas Fir) wood that is found at the home centers.

I used this white wood because it was the cheapest wood available. I didn't care about the knots because I planned to paint it white to match the woodwork in the room. All of the wood used totaled around $40, but the foil bubble insulation cost another $20.

The only wood that was not white wood was the top and the plywood back. I bought a higher quality, 4' x 1' solid pine panel for the top because I didn't want it to warp or crack. I bought a 4' x 2' sheet of 1/4" plywood for the back.

You will need:
~18' of 1 x 2 whitewood
~11' of 1 x 3 whitewood
~4'  of 1 x 4 whitewood
1" x 12" x 4' solid pine panel
4' x 2' sheet of 1/4" plywood

Keep in mind, this is for a 32" wide x 25" tall x 10" deep radiator. You will probably need to modify these measurements to make it fit your radiator and house.


Instructional Sites
This Old House
Easy2DIY


Step 5: Rough Cuts & Doweling

I started by making a cut list, which can be seen on the previous page. I then made the rough cuts on each piece of wood, and laid them out on the floor. Once all of the pieces were cut to length, I notched the corners of the legs and around the vent opening at the top.

I started the assembly with the side pieces because they seemed to be a simpler task than the front piece. I used my cheap doweling jig to make uniform, precise holes in the ends of the slats. The drill stop allowed me to make the holes just a little deeper than half the length of the dowels. This will make sure that I get the desired strength from the joint, and the dowel's length won't be all on one side of the joint.

Step 6: Pocket Holes

Once the holes were drilled on the slat, I marked the center of the rail and made matching holes here to accept the dowels from the slat.

I didn't have this jig when I built the original cover, so I relied on other joints and a few pocket holes. The pocket holes I did use were cut by hand and did not come out as I had hoped. They worked, but I don't recommend it, you are better off buying the jig.

Now that I have the jig, it is much easier to make this joint and I recommend using pocket holes for all joints but the slats. They make a really nice tight fit and the fasteners are all well hidden. I am now building another radiator cover using nothing but pocket screws.

The pictures below show how I used the pocket hole jig to secure the rail (horizontal piece) to the stile (vertical piece). Just follow the directions included with the Jig. The positioning of the jig and the required length of the drill bit are determined by the thickness of boards you use.

Each rail should get 2 dowel holes on each end and on the side for the slats. Where the rail meets the stile, you should also use a pocket screw. Once the sides were assembled, I moved onto the front piece using the same method.

Step 7: Rabbet Joint

I had a router, but the bearing bits are only good for certain jobs. To shape long boards and get decent results, you need a router table. I didn't feel like buying one, so I bought some machine screws that were the right size and modified a cheap portable workbench that I had to hold my router upside down. I mounted a piece of plywood and some scrap wood as a fence and I now had something that would work as a router table.

I ran the back, inside edge of the two sides through the router with a straight cut bit. This created a nice rabbet that I could seat the plywood back into, so it wouldn't show from the sides.

To smooth the edges of the pine top, I used a 1/2" roundover bit to ease 3 of the sides of the panel. I left the back edge unfinished so it will stay flush against the wall.

Step 8: Final Assembly

Now the sides are put together and the back edges are rabbeted. The front piece was assembled with the same process as the sides, but without the rabbet.

Clamp the sides to the front and join them with 2 more pocket screws per joint. Next cut the plywood to size, fit it into the rabbet and nail it in place. Now you can secure the top with the routed edge to the rest of the cover. I used finishing nails since I was going to paint it, but you could use a pocket screw if you were planing to stain the wood and didn't want the nails to show.

Step 9: Placement

When I slid the cover over the radiator, it got hung up on the shoe molding, so I had to mark the edges of the cover on the molding and cut it out. To cut the molding without taking it off the wall, I used a multi-master-like tool that I got from Harbor Freight for about $40. This tool allows you to cut something without removing it and it will not harm anything else in the area.

Step 10: Update...


After a year of use, the heat made the wood shrink and swell. A few gaps opened up so I filled the gaps with painter's caulk. Because it's acrylic caulk, it resists cracking and is more flexible than wood putty or painter's putty.

I also painted the radiator and the inside of the cover black. This way, the radiator doesn't show through the slats and the foil insulation is less noticeable in the back.

Comments

author
CourtneyT made it! (author)2015-08-23

W made it! Thanks for the great instructions. My husband and I have been trying to find nice radiator covers for the 3 years that we've owned our home, and nothing has come close to being this simple and this nice. The hardest part is calculating the dimensions needed, but once that's all mapped out, the measuring, cutting and assembling is so easy. We used the pocket hole jig for the entire assembly, including anchoring the top shelf. You're instructions explained everything so nicely that we didn't have any problems along the way. It's the end of August right now, so I don't have comment on the effect it has on heating the space, but we have high hopes that it will help move the hot air into the room more efficiently.

IMG_20150823_104606.jpg
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JmsDwh (author)CourtneyT2015-08-23

Wow! Very nice! I was very happy with that radiator cover, but unfortunately we left it behind when we sold that house. I have mostly recessed radiators in this house, but I have been planning to make a few more of these. The foil insulation throws a lot of the radiant heat back into the room, and the convection shape definitely changes the airflow around the radiator. I hope it treats you well this winter.

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vlad1010 (author)2015-03-19

This is a lot better looking then the covers with the metal mesh. I like the style. How did you connect the two side to the front?

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JmsDwh (author)vlad10102015-04-01

Thanks! I actually screwed through the front face to the sides with countersunk screws and then filled the holes with wood putty. I knew I was going to paint the cover and since I was using very light plywood for the back I wanted to make sure it was very sturdy. I made the dimension very tight to the edges of the radiator so I didn't want to expand the size to allow for internal braces so I went with the screws through the face.

author
SWV1787 (author)2010-10-03

This is a very nice build. You have a good to the point Instructable, but I don't know of too many people in my area who still have radiators in their home.

author
clrcopy (author)SWV17872012-11-08

Seriously? I live in a town of 3200 and I bet a 1/4 do, go out into the county and probably equal that many or more and this is just one rural area. Houses that were built in the early 1900's are common to have them. Ours are water vs. steam, and actually very efficient heat for our area. NE Iowa gets cold, in fact watching This Old House, you see them very frequently on that show, again a very cold area. If you live in a warmer region, not as practical, but for us, 0 degree days for months, great way to heat our house.

author
caitlin.walbrun (author)clrcopy2014-12-01

I'm sure they are more common in older cities too and maybe those with colder climates because having central air isn't as big a deal. I live in an urban area full of turn of the century homes (Minneapolis/St. Paul). My house was built in 1913 and that is by no means unusual. A lot of the old homes and other buildings still have radiators, including ours. Always on the lookout for covers because, while I love my radiators, I also need a place to set a lamp!

author
JmsDwh (author)caitlin.walbrun2014-12-05

Thanks for the comment. I recently moved and had to leave this cover behind in my old house but I will be making and modifying a few for my new house soon. We looked at a lot of houses in this town and the whole town is filled with steam heated houses and most of them have the original radiators. I think steam and hot water cast-iron radiators are most common in the North-central and Northeast US.

author
JulieB1 (author)2014-09-16

This looks great - but how do you access the radiator knobs? Do you just move the whole cover? Maybe a little door could be built into the side that has a latch to keep kid's fingers out of harm's way?

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PaulM2 (author)2014-07-30

Nice job! Though I read someplace that the reason most radiators are placed in front of windows is to reverse the "cold" convection that the cold air coming off the windows produces... and so I'd think it would be important to allow the hot air to rise unimpeded. You could always cut out some holes in the top and add that metal grating.. or perhaps adding a slight pitch to the underside of the lid would enable the heat to more readily exit the top-front. Although, maybe this is not as big a deal with today's better insulated windows.

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justjordy33 (author)2012-08-14

Great job on the post. The insulation looks pretty well done.

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TomMontana (author)2011-01-10

Great job. I really like the look of this cover. The lack of a metal grill and straight lines really make this a sharp and contemporary looking piece.

1) Did you anchor it snug against the wall so nothing falls into the back or just let the weight of the cover keep itself in place?

2) How is the cover working now that it is winter? Any noticeable difference?

author
JmsDwh (author)TomMontana2011-01-12

Thanks a lot.

I didn't anchor the cover against the wall. The 1/4" plywood fits flush up against the wall and there is very little space between the back of the radiator and the wall, so it wasn't necessary for me.

I am very happy with how the cover works. It definitely helps warm the room and it protects my kids from the radiator. Its also nice that it can be used as a little display shelf for my daughter's stuffed animals.

My only complaint with this project is that the wood expands and contracts unevenly because of the extra heat. I noticed that some of the slats had small gaps at the ends where they med with the rails. I have some painter's acrylic latex caulk that I plan to fill those gaps with and touch up the paint.

On my next cover I plan to use mortise and tenon joints at the end of the slats. These will replace the dowels and hopefully give me a tighter fit.

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EDNA KEENAN (author)2010-10-06

Your design is reall nice and good looking... Well done!

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EDNA KEENAN (author)2010-10-06

Steam heat is the best hot water raditors not true that people don't have heating systems..... Long Island, New York Housing Buildings and New Jersey & alot of Apartment still have HOT WATER HEAT......

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anita018 (author)2010-10-05

This design is ridiculously amazing. I wish they were mass produced by the amish so I could buy 12.

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davon (author)2010-10-05

Every Radiator Cover isn't efficient...the insulation behind it is a good idea, but the cover maintain the hot inside the radiator, only insulation in back of the radiator is better.

author
JmsDwh (author)davon2010-10-05

True, most radiator covers limit the amount of heat that reaches the rest of the room, but I left plenty of space for the radiant heat to escape. The added feature of using the natural convection of hot air around the radiator to push the heat out into the room makes this a more efficient way to heat the room. This type of design would be especially helpful to get heat up and over an obstacle like a couch that wouldn't fit elsewhere in the room.

author
improprietary (author)2010-10-05

a good looking radiator cover you got there, nice touch with the insulation but you mention the effectiveness a few times, as to how much hot air gets trapped and so forth.
If you got the spare parts laying around you can put some 80mm fans or bigger right at the skirt of it so it blows air up, 12v tranformers 'should' be cheap for this purpose, frankly i don't know. Just a thought

author
JmsDwh (author)improprietary2010-10-05

That would be cool, but I also like the simplicity of a convection only design. It really is surprising how much hot air is directed out into the room by the top vent.

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pnwheel4 (author)2010-10-04

I have not been on the site recently and was pleased to find your instructable. I have steam radiators in my home and have been brainstorming what to cover them with. The flimsy metal ones are actually pretty expensive-so this is great. Thanks for your help. And the graphics are pretty cool--how did you get them?

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CICCI (author)2010-10-04

Does radiator cover presents a fire risk?

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JmsDwh (author)CICCI2010-10-04

For a steam or hot water radiator, I would say there is no risk of fire. Hot water radiators are always below water's boiling temperature of 212 degrees F (depending on your elevation). Steam, under normal pressure at sea level will not be much hotter than that because as soon as it boils in the boiler, it travels up the pipes to the radiators. Because wood will combust at 450 degrees F, I don't think there is any risk of fire.

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JmsDwh (author)JmsDwh2010-10-04

Electric radiators may be a different story. I know they can get a lot hotter and can burn fabric if couches or curtains are too close to them.

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bicygirl (author)2010-10-04

You did a great job with this instructable. Although I don't have a radiator in my home, I still benefited by learning a little more about furniture construction and tools that I didn't know about. In the future I may have the courage to try a simple furniture project. You are a very clear and thorough in your explanations. Thanks!

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Cat on my Lap (author)2010-10-03

Can you post a link to the Harbor Freight item? I am intrigued.

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JmsDwh (author)Cat on my Lap2010-10-03

You mean this one?
http://www.harborfreight.com/self-centering-doweling-jig-41345.html

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Cat on my Lap (author)JmsDwh2010-10-03

I meant the one seen in step 9.

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JmsDwh (author)Cat on my Lap2010-10-03

Ok, here it is...
http://www.harborfreight.com/multifunction-power-tool-67256.html

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