I would say no because the furnace is turned off & on by thermostat which also control how long it runs. Which means it runs until satisfied at the location it mount ( where hangs). If you close a supply vent, and room has leak windows or air infiltration problem. This could create ( not say it will) a negative pressure in room- allowing the return to suck threw cold air threw leak windows, walls , ceilings. which if was real bad cold increase heat cost alittle. It is better to have air return and supply open in all rooms not be block by furniture to be balanced in positive and negative air pressure. In my opinion it bad to block off vents, it will not make the furnace run any less. _____ at this point i turn simple question in more_________ Turning up furnace by pro, programmable set t-stat, seal of duct work at every joint, change air 1 month or checking. will save money or replace 16-2o year furnace with high efficiency models. for your home: air seal home from air filtration> Basement & attic are two big area's Right amount of insulation in attic makes big difference. Saves on Furnace and a/c bills leak door seals , can lights if have alot them, windows, skylights If have basement air seal the sill by clauking sill & rim joist. electric outlets foam seals. Note: some gas company like my local one offer home testing fro 50.00 bucks , the tell what improvement can be made to to your how to save money, plus the offer rebates to you in you use the contractors to make the improves- win win. You may not want all that but you got it.

I have a recommendation for whole-house fans, and that is to go with the ones made by Triangle Engineering of Arkansas (made in the USA!). These things move more air than any other brand. As an example: the 36" belt-drive model sold at Lowes & Home Depot moves 6,900 CFM on its highest speed. The 36" one that Triangle makes moves 10,600 CFM. I just put one of these in last week and am so taken with it that I'm evangelizing for Triangle now. These things are much higher quality than the other brands too -- these are made with very heavy-gauge solid welded steel (as opposed to the thin, flimsy metal - often aluminum - that other brands use). They use a very solid motor made by Emerson, the best of the top three motor-making companies (the other two being Fasco and A.O. Smith). They come pre-framed on a wood frame for installation, AND they have sponge-rubber noise-dampening material between the fan and the frame, so they are much quieter than the other brands. Also, Triangle holds a patent on an automatic belt-tensioning system these things use, so you don't have to worry about getting the tension right when you install the fan (or in the years thereafter as the belt loosens up). Also, they come in more sizes than the other companies -- from 24" all the way up to 48" blade diameter (which moves a ridiculously whopping amount of air; no one else makes one that big). They're sold online at Southern Tool amongst other places that ship nationwide, so they're available wherever you live. Also, Triangle re-brands some of these as a private label for Dayton, which is the "store brand" of Grainger - so if you have a Grainger store near you (check your phone book or their website), you can buy one there. I will say this, though - Grainger/Dayton makes their own shutters, and those shutters are much better than the one Triangle makes. Triangle makes great fans, but crappy shutters. Luckily, they're sold separately -- so buy a Triangle fan and Dayton shutters; money can't buy better products. They also re-brand some for a company out in San Francisco called "Fanman" (a/k/a "Delta Breeze"). A word to the wise -- these fans move a lot of air, so make sure to install at least the recommended minimum amount of attic exhaust space (gable vents, soffit vents, roof vents, some combination thereof, whatever works for you) - if you don't have enough, the fan will operate at reduced capacity, and there will be a backpressure which will cause the shutters to rattle when the fan is in operation (any time you hear whole-house fan shutters rattling, you know there isn't enough exhaust space). Oh, and one other thing -- only buy a belt-drive whole-house fan, don't EVER buy a direct-drive model...the direct-drive models are at least five times louder, they sound like standing on an airport runway next to an old prop plane getting ready to take off. Several of the dedicated whole-house fan installing companies have chosen to use Triangle fans; that should tell you something. These companies want satisfied customers, so they use Triangle and only Triangle. Refer to http://www.trianglefans.com/wholehouse.html for more info Here is a link that might be useful: Triangle whole-house fans

You have an "attic insulation shield" in place now so insulation can go directly against that part, but not above it and contact the chimney pipe itself. I don't think a bit of air circulation is a bad thing around that flue. It would give more even temperatures along the pipe.

These vents were probably installed prevent moisture problems in your home. Older homes were not always built with kiln dried lumber and can be prone to sweat as they dry -- hopefully, since this is an older structure, most of the drying is done. Do not, therefore, permanently cover this vent entirely with solid material. You could remove the vent grill -- but only temporarily -- and add to the vent frame inside -- just inside the existing opening -- so you can add a window inside that opens inward via side hinges or slides open as a patio door. Then after any refinishing and/or painting, add the vent back to the outside. If you cannot find an arch to fit the window and/or if custom windows are not in your budget, you could get a rectangle window and cover the arch part of the opening above it with a solid piece of wood or glass. You need to be able to open the window if you encounter sweating/moisture problems later -- and, if you add a screen to the back of the vent before putting it back in place, you may find that opening these windows minimizes the need for AC. https://i.pinimg.com/564x/9d/27/d8/9d27d834018e3a300a74dbe6c7e0eed9.jpg https://danmer.com/site-content/images/creative/product-icons/browse-by/bathroom-small-windows.jpg https://sc01.alicdn.com/kf/HTB10OloSXXXXXaXXFXXq6xXFXXX5/Durable-china-supplier-aluminium-small-casement-window.jpg http://abbieblog.com/wp-content/uploads/ideas-design-for-arched-window-mirror-Beautiful-window-arch-mirror-Austin-Antique-Arched-Window-Mirror-amiable-_fascinate-small-arch-window-mirror_dreadful-cream-arch-window-mirror_unbelievable-mediev.jpg http://froughol.com/i/2017/10/small-window-designs-for-homes-window-designs-for-homes-home-design-ideas.jpg