I found that the state in the House Average Humidity template was loosing the "vals" variable outside the for loop. I updated the variable to use a namespace and that resolved the issue for me.
{# >>> EDIT THESE ENTITY IDS TO MATCH YOUR SENSORS <<< #}
{% set rooms = ['sensor.lennox_thermostat_humidity'] %}
{% set params = namespace(vals = []) %}
{% for e in rooms %}
{% set s = states(e) %}
{% if s not in ['unknown', 'unavailable', 'none', ''] %}
{% set params.vals = params.vals + [ s|float ] %}
{% endif %}
{% endfor %}
{% if params.vals|length == 0 %}
unknown
{% else %}
{{ (params.vals|sum / params.vals|length)|round(1) }}
{% endif %}
I found that the state in the House Average Humidity template was loosing the "vals" variable outside the for loop. I updated the variable to use a namespace and that resolved the issue for me.
I'm on HA 2026.1.2