Parsing Strings and Integers in JavaScript

I am new to JavaScript and HTML and am hoping someone can notice what I am doing wrong (I’m sure it is probably something small that I am just missing). I have been looking at this for a while, and I cannot seem to figure it out.

The problem is that branch #2 (identified in the comment within the code) is returning NaN for the houseVal which is supposed to return either sf for single-family or tw for townhouse/condo.

I have a JavaScript form I am making. Here it is:

function getPrice() {
        var form = document.getElementById("calc");
        var out = form.elements["z"];
        //get numbers
        var sqftVal = parseInt(form.elements["sqft"].value);
        var bathsVal = parseInt(form.elements["baths"].value);
        var builtVal = parseInt(form.elements["built"].value);
        var lotVal = parseInt(form.elements["lot"].value);

        for (i = 0; i < document.forms[0].zipcode.length; i++) {
          if (document.forms[0].zipcode[i].checked) {
            var zipVal = parseInt(document.forms[0].zipcode[i].value);
          }
        }

        for (i = 0; i < document.forms[0].gar.length; i++) {
          if (document.forms[0].gar[i].checked) {
            var garageVal = parseInt(document.forms[0].gar[i].value);
          }
        }

        for (i = 0; i < document.forms[0].housetype.length; i++) {
          if (document.forms[0].housetype[i].checked) {
            var houseVal = parseInt(document.forms[0].housetype[i].value);
          }
        }
          
        if (zipVal == "47") {
            if (garageVal == "2") {
                if (houseVal == "sf") {
                    out.value = 1; 
                }
                else { //townhouse
                    out.value = houseVal; // <------ PROBLEM: returns NaN <------------
                }
            }
            else { //garage == 3
                if (houseVal == "sf") {
                    out.value = 3; 
                }
                else { //townhouse
                    out.value = 4;
                }
            }
        }
        else { //zip == 20148
            if (garageVal == "2") {
                if (houseVal == "sf") {
                    out.value = 5; 
                }
                else { //townhouse
                    out.value = 6; 
                }
            }
            else { //garage == 3
                if (houseVal == "sf") {
                    out.value = 7; 

                }
                else { //townhouse
                    out.value = 8; 
                    
                }
            }
        }
      }
    </script>

and here is the Home Type (e.g., Single Family or Townhouse/Condo) part of the form.

...
<fieldset>
        <legend>House Type</legend>
        <div>
          <input type="radio" id="sf" name="housetype" value="sf" />
          <label for="sf">Single Family</label>
        </div>
        <div>
          <input type="radio" id="tw" name="housetype" value="tw" />
          <label for="tw">Townhouse/Condo</label>
        </div>
</fieldset>
...

var houseVal = parseInt(document.forms[0].housetype[i].value);

        for (i = 0; i < document.forms[0].housetype.length; i++) {
          if (document.forms[0].housetype[i].checked) {
            var houseVal = parseInt(document.forms[0].housetype[i].value);
          }
        }

        for (i = 0; i < document.forms[0].housetype.length; i++) {
          if (document.forms[0].housetype[i].checked) {
            var houseVal = document.forms[0].housetype[i].value;
          }
        }