It will vary on the room type and construction. However you can assume you want 10-15 watts of energy per square ft. That would mean you want 2500-3750 watts total, which would be 8,500 - 12,750 BTU's (3.4 BTUs/Watt).
References:
How_many_square_feet_does_a_5000_BTU_heater_heat
http://www.diychatroom.com/f18/btus-watts-35066/
It is 250/1000 which can be simplified, if required.
It is 250/3000 which can be simplified, if required.
It is 250/1000. You can simplify this fraction if required.
7,803,495 BTU's Assuming it's water that's being heated and the temperature is Fahrenheit: 500*250*62.42796 (<the weight of one cubic foot of water)= 7,803,495 BTU's
If the given dimensions are in feet then there are 25 times 10 = 250 square feet
59.711 kilo calories of heat are produced from 250 kilojoules. 5 kilojoules are equivalent to 1 kilo calorie of heat.
250 square foot
The specific heat capacity of copper is 0.385 J/g°C. To calculate the heat required, you use the formula Q = mcΔT, where Q is the heat energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. Plugging in the values, Q = 250 g x 0.385 J/g°C x (150°C - 10°C) = 8750 J.
The 2009 Lexus IS-250 has 52.7 in. of rear shoulder room.
The 2013 Lexus IS-250 has 54.1 in. of front hip room.
The 2006 Lexus IS-250 has 52.7 in. of rear shoulder room.
The 2011 Lexus IS-250 has 53.7 in. of rear hip room.
The 2007 Lexus IS-250 has 30.6 in. of rear leg room.
The 2010 Lexus IS-250 has 30.6 in. of rear leg room.
The 2013 Lexus IS-250 has 37.2 in. of front head room.
The 2010 Lexus IS-250 has 43.9 in. of front leg room.
The 2007 Lexus IS-250 has 54.4 in. of front shoulder room.