Hi I have a fireplace in a cottage that is seasonal in northern wisconsin wanting to get any extra heat we csn aside from space heaters. Looked into putting woodstove insert in fireplace but cost prohibitive due to small 4 inch flue opening per chimney sweep. He suggested a heat reflector shield for $200 in back to reflect 40% more hest in cottage v. Up chimney. Does anyone have familiarity with these &do they really help? Also any other reasonable ideas for added heat are appreciated. I am looking into a hydronic 240v baseboard heater installation also. Thank you