it depends on how close you have it to them. I have 6 three day olds and am using a 100 watt regular light bulb in the metal heat lamp cone. i have it 8 inches off of the towl in the box. temp reads 90-95 as well. BUT they do have room in the box to get away from the heat. I put their food and water in the cooler areas. they know what temp. they are comfortable at and will move in and out of it as desired. If they are all backing away from the heat they are to hot. If they move in to it and are huddled one on top of each other they are cold. if they lay around under it sprawled out like a fur rug next to each other they are happy, content and loving life.
I have read that it is very important to have the extra area where they can get away from the heat lamp. My 6 are in a 2 by 3 cardboard box. the heat lamp covers about 1/3rd of the box, 1/3 get the light, but very little heat, and 1/2 gets the light, but no heat.
Mine are in the house as well. 95 is to hot for mine, they seem comfortable at 85 - 90 right now.