Please choose the correct ending to complete the given sentence: Home and Garden: [header] How to buy a wood burning stove [title] Consider your heating needs by evaluating the size of your home. [step] You will need to determine the heat load necessary to maintain the square footage of the area you want heated. Heat load is measured in btus, or british thermal units.

Ending1: Inquire about btus and thermal units using online resources. [substeps] Btus heat packs can be found at home improvement stores, department stores, and some gas stations. Ending2: To determine how much heat you need, pay attention to the dimensions of each room you intend to fire in. [substeps] The larger the square footage, the larger your fire seats will need to be. Ending3: You will need 25 to 30 btus per square foot. [substeps] Measure each room to be heated with measuring tape. Ending4: Btus are rated from 2000-1000. Btus can be changed or altered depending on the size of your home.

Answer format: ending1/ending2/ending3/ending4